Question about 2002 GMC Sonoma Extended Cab

1 Answer

Code engine p0300

Random misfires. Replaced all wires, cap, button, plugs, spider injector, coil, coil pick up, No manifold or vac leaks. 2 yr old fuel pump, new battery. Has dist. shaft removed and inspected. Told there is no EGR valve on this model to replace. New fuel filter. K&N air filter. New MAF sensor.

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  • 66 Answers

I had the same exact problem with my 2000 blazer. I replaced the same things you did. It didn't matter what i did to it i still had the same problem. There was a heavy smell of gas when it was running and a lot of smoke. Here's what i did to fix this. After i replaced the spider injection ($350) i still had the problem so i figured something was telling this thing to stay wide open, which is constantly pouring gas on the spark plugs. Next i unhooked the wiring harness that plugs into the new spider injection (the one on top with about 12 wires). Then i set my multimeter to ohms and grounded the black one and then check each contact inside that harness. I forget now but i'm pretty sure 6 of those should be grounded and the other 6 pulse a signal. Anyway i found that 1 wire that shouldn't be a ground was so i traced that wire back and found a very small crack and instead of being orange about a 1/4 inch of the wire was green. I replaced a section of wire here put on some shrink wrap and it started and ran like new again. I only wish i would have spotted this before i started guessing and spending and listening to know it all's. I don't think i had the key on when i was i checking to see what wires were grounded. Let me know if this helps you.

Posted on Apr 18, 2014

  • Richard John
    Richard John Apr 21, 2014

    The wiring was harness for the spider injector all checked out, but you sparked me to check everything else. The MAP sensor ended up not being with the correct voltage. I replaced it and it seems to have done the trick. I drove it for over an hour with the A?C going and there's no more engine light or skipping. Thanks Robert for setting me on the right track. Hopefully it continues to work, I couldn't have done it without you!

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Posted on Jan 02, 2017

emissionwiz
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SOURCE: Misfires 96 gmc sierra 5.0

I suggest you have the injectors tested by the dealer, the sludge buildup will not cause a miss fire. to clean the throttle body use carberator spray while holding the engine idle high.

Posted on Aug 05, 2009

motor1258
  • 6674 Answers

SOURCE: GMC SAFARI 2001 4WD. RANDOM MISFIRE DETECTED

2 things come to mind, confirm you have proper fuel pressure, and if you've got a MAF (mass air flow sensor)
in the intake hose to throttle body, remove it, and spray it clean with Tuner spray cleaner, or electrical spray cleaner from radio shack or similar store, and then try it. Not uncommon for the MAF sensor to dirty and cause what your experiencing. If that doesn't cure it, start checking EGR and EVAP system.

Posted on Mar 02, 2010

SOURCE: Bad idle on my 1995 GMC Jimmy. 4.3 Vortec CPI

Unfortunetly....these spider injectors and fuel pumps can have very similar symptoms when failing. What I do know is I work on this motor more than any other motor in my shop. Very common with fuel problems...and I can comfortably tell you that they updated the injector kits on these car for a reason. The original model is junk. I have done these on just about every one of my cutomers vehicles over 150,000 miles. However, I am not going to tell you that is your problem....but it sounds fuel related. Did/does your vehicle skip? Leaking injectors will usually cause a skip due to shortage of fuel to that cylinder. I also have a computer that allows me to monitor the firing of each cylinder, and do an injector kill test. This is what I would do first. Unfortunetly, sounds like you can't so start with this: Clean your throttle body. The pintle that the IAC motor pushes in and out goes into a small port. Spray that port out with carb clean. Get a fine wire brush and get that throttle body clean and shinny. That pintle can easily stick on existing carbon in that port...new part or not. Check for vacuum leaking with carb clean...spray it around the intake and vacuum hoses...see if any particular spot changes how it runs when you spray it. Do you have a vacuum gauge? what is manifold vacuum? Since you are in the intake...make sure your puddled fuel is not due to pulling the main lines off the the injector assembly. After intake is off. hook fuel lines and harnes back up to injector assembly. key up (no start) vehicle...this pressurizes fuel system. look for leaking. The fuel pressure regulator is built on to the side of that assembly....its the round diaphragm with the tube coming out of it. If it leaks fuel out...that may be your problem. And you can replace that without doing the whole injector kit...fairly cheap. If not fixed....what is your fuel pressure. You need to have 60-64 PSI at key up. Try the carbon build up and intake test first...both quick, easy, and cheap. If this is not your issues...its sounds fuel related....just want to confirm that you don have a misfire/skip. That could change diagnosis quite a bit. Keep me posted....more than happy to help. By the way....I own all GM's too...lol...haven't learned my lesson yet

Posted on Nov 14, 2010

  • 88 Answers

SOURCE: 1998 gmc k1500 random misfires

There is more than just ignition that could be the issue, including fuel injectors and EGR. Try this link to see if you get more ideas:

http://www.engine-light-help.com/P0300-check-engine-light.html

Posted on Nov 26, 2010

  • 18 Answers

SOURCE: My 2001 GMC Safari has

Look and make sure your computer is good! PCM could be failing you! Injectors don't really go bad! Also look at you fuel pressure make sure it's strong!

Posted on Sep 05, 2011

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How to check coil packs and spark plugs wire with a multimeter. ..having random/ multiple misfire P0300...need to know their spec? 97 Cadillac Deville, 4.6 engine/Northstar


I don't think you really understand what this fault code means, it means that likely all the engine cylinders are misfiring at random no set pattern, not any particular cylinder. I would start with checking for engine vacuum leaks like the intake manifold gasket. that is all I can say since you provided no make, model or year and engine type and size information.

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P0300 Diagnostic Code - Random Misfire Technical Description Random/Multiple Cylinder Misfire Detected What does that mean? Basically this means that the the car's computer has detected that not all of the engine's cylinders are firing properly. A P0300 diagnostic code indicates a random or multiple misfire. If the last digit is a number other than zero, it corresponds to the cylinder number that is misfiring. A P0302 code, for example, would tell you cylinder number two is misfiring. Unfortunately, a P0300 doesn't tell you specifically which cylinder(s) is/are mis-firing, nor why. Symptoms Symptoms may include: the engine may be harder to start the engine may stumble / stumble, and/or hesitate other symptoms may also be present Causes A code P0300 may mean that one or more of the following has happened: Faulty spark plugs or wires Faulty coil (pack) Faulty oxygen sensor(s) Faulty fuel injector(s) Burned exhaust valve Faulty catalytic converter(s) Stuck/blocked/leaking EGR valve / passages Faulty camshaft position sensor Defective computer Possible Solutions If there are no symptoms, the simplest thing to do is to reset the code and see if it comes back. If there are symptoms such as the engine is stumbling or hesitating, check all wiring and connectors that lead to the cylinders (i.e. spark plugs). Depending on how long the ignition components have been in the car, it may be a good idea to replace them as part of your regular maintenance schedule. I would suggest spark plugs, spark plug wires, distributor cap, and rotor (if applicable). Otherwise, check the coils (a.k.a. coil packs). In some cases, the catalytic converter has gone bad. If you smell rotten eggs in the exhaust, your cat converter needs to be replaced. I've also heard in other cases the problems were faulty fuel injectors. Random misfires that jump around from one cylinder to another (read: P030x codes) also will set a P0300 code. The underlying cause is often a lean fuel condition, which may be due to a vacuum leak in the intake manifold or unmetered air getting past the airflow sensor, or an EGR valve that is stuck open. It is helpful to have access to a factory service manual and an advanced scan tool to properly diagnose a random misfire DTC. P0300 Diagnostics Video Here is a helpful video that may assist you in learning more, diagnosing, and repairing your P0300 DTC. This video is intended for auto repair professionals but could be helpful to DIYers. It shows use of an advanced OBD-II scan tool during diagnostic steps:

Read more at: http://www.obd-codes.com/p0300
Copyright © OBD-Codes.com Autolite Challenge Series P0300 Engine Misfire Diagnosis

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Why the loss of power and po300 code?


HARD TO SAY WITH OUT BEING THERE BUT THIS MIGHT HELP .
Crankshaft sensor Was the trouble with my 99 Chevy truck after replacing many components like coil cap rotor wires and so on .
http://www.obd-codes.com/p0102 Code P0300 Causes and Fixes Code p0300 is a code that is generated when your engine has a misfire that is not related to only one cylinder. Sometimes this code will be set in addition to other codes such as p0301 which means that there is a misfire on cylinder 1 (cylinder 1 is the number one cylinder when looking at the firing order. It is generally the forward most cylinder on the engine.). If these engine codes are present as well the you should diagnose those first as they are probably causing code p0300.
This code will set your check engine light and needs to be fixed as soon as possible. If it is not then you will probably need to replace your catalytic converter as well as the problem that is causing your misfire.
There are many causes for this obd code. Since it is a "random misfire" or "multiple misfire" this means that the misfire is on different cylinders and not just one all the time.
Common Causes
  • Low Fuel Pressure
  • Vacuum Leak
  • EGR system malfunction
  • Internal Engine Problems (such as low compression)
Less Common Causes
  • Faulty Coil
  • Faulty Spark Plugs and/or Wires
  • Camshaft or Crankshaft sensors
  • Ignition module
  • Computer

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Egr valve for 1997 cheve Blazer code is 0300 misfireing what could be the trouble


usually this code is followed by another number 1-4 or 1-6 or 1-8 depending on how many cylinders your vehicle has ,, what the code you got is a basic P0300 Random/Multiple Cylinder Misfire Detected A code P0300 may mean that one or more of the following has happened:
  • Faulty spark plugs or wires
  • Faulty coil (pack)
  • Faulty oxygen sensor(s)
  • Faulty fuel injector(s)
  • Burned exhaust valve
  • Faulty catalytic converter(s)
  • Stuck/blocked EGR valve / passages
  • Faulty camshaft position sensor
  • Defective computer
  • I would suggest spark plugs, spark plug wires, distributor cap, and rotor (if applicable). Otherwise, check the coils (a.k.a. coil packs). In some cases, the catalytic converter has gone bad. If you smell rotten eggs in the exhaust, your cat converter needs to be replaced. I've also heard in other cases the problems were faulty fuel injectors.
    Random misfires that jump around from one cylinder to another (read: P030x codes) also will set a P0300 code. The underlying cause is often a lean fuel condition, which may be due to a vacuum leak in the intake manifold or unmetered air getting past the airflow sensor, or an EGR valve that is stuck ope

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2 Answers

Engine cranks but wont start has an obd p 300 &p304 help me


P0300 Random/Multiple Cylinder Misfire Detected, the 304 is for cylinder number 4 any of these could be wrong If there are symptoms such as the engine is stumbling or hesitating, check all wiring and connectors that lead to the cylinders (i.e. spark plugs). Depending on how long the ignition components have been in the car, it may be a good idea to replace them as part of your regular maintenance schedule. I would suggest spark plugs, spark plug wires, distributor cap, and rotor (if applicable). Otherwise, check the coils (a.k.a. coil packs). In some cases, the catalytic converter has gone bad. If you smell rotten eggs in the exhaust, your cat converter needs to be replaced. I've also heard in other cases the problems were faulty fuel injectors. Random misfires that jump around from one cylinder to another (read: P030x codes) also will set a P0300 code. The underlying cause is often a lean fuel condition, which may be due to a vacuum leak in the intake manifold or unmetered air getting past the airflow sensor, or an EGR valve that is stuck open

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1 Answer

PO300 code. 3.4L 98 Chevy blazer. (random misfire). this happens at high speeds 16000 rpms and higher. after the engine is warm it is more noticeable and misses at idling speeds. if i take it higher than...


A P0300 diagnostic code indicates a random or multiple misfire. If the last digit is a number other than zero, it corresponds to the cylinder number that is misfiring. A P0302 code, for example, would tell you cylinder number two is misfiring. Unfortunately, a P0300 doesn't tell you specifically which cylinder(s) is/are mis-firing, nor why. it could be any of the following A code P0300 may mean that one or more of the following has happened:
  • Faulty spark plugs or wires
  • Faulty coil (pack)
  • Faulty oxygen sensor(s)
  • Faulty fuel injector(s)
  • Burned exhaust valve
  • Faulty catalytic converter(s)
  • Stuck/blocked EGR valve / passages
  • Faulty camshaft position sensor
  • Defective computer
  • also
  • Random misfires that jump around from one cylinder to another (read: P030x codes) also will set a P0300 code. The underlying cause is often a lean fuel condition, which may be due to a vacuum leak in the intake manifold or unmetered air getting past the airflow sensor, or an EGR valve that is stuck open.

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2 Answers

Error code P0300


A P0300 diagnostic code indicates a random or multiple misfire
If there are no symptoms, the simplest thing to do is to reset the code and see if it comes back
Symptoms may include:
  • the engine may be harder to start
  • the engine may stumble / stumble, and/or hesitate
  • other symptoms may also be present

A code P0300 may mean that one or more of the following has happened:

  • Faulty spark plugs or wires
  • Faulty coil (pack)
  • Faulty oxygen sensor(s)
  • Faulty fuel injector(s)
  • Burned exhaust valve
  • Faulty catalytic converter(s)
  • Stuck/blocked EGR valve / passages
  • Faulty camshaft position sensor
  • Defective computer

If there are symptoms such as the engine is stumbling or hesitating, check all wiring and connectors that lead to the cylinders ( spark plugs). Depending on how long the ignition components have been in the car, it may be a good idea to replace them as part of your regular maintenance schedule. I would suggest spark plugs, spark plug wires, distributor cap, and rotor (if applicable). Otherwise, check the coils (coil packs). In some cases, the catalytic converter has gone bad. If you smell rotten eggs in the exhaust, your cat converter needs to be replaced. I've also heard in other cases the problems were faulty fuel injectors.

Random misfires that jump around from one cylinder to another (read: P030x codes) also will set a P0300 code. The underlying cause is often a lean fuel condition, which may be due to a vacuum leak in the intake manifold or unmetered air getting past the airflow sensor, or an EGR valve that is stuck open

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4 Answers

2004 Acura MDX 3.5 130,000 miles multiple missfire how do i fix ?


Hi, multiple cylinder misfire, is when the engine cylinders do not fire in the correct order, and do not do it constantly. There is no particular pattern to it. My experience with this condition is that it is usually caused by a faulty ignition coil that is beginning to burn out. It could also be bad wires pluds rotor or cap

Causes Include.
  • Faulty spark plugs or wires
  • Faulty coil (pack)
  • Faulty oxygen sensor(s)
  • Faulty fuel injector(s)
  • Burned exhaust valve
  • Faulty catalytic converter(s)
  • Stuck/blocked EGR valve / passages
  • Faulty camshaft position sensor
  • Defective computer

Possible Solution:
If there are symptoms such as the engine is stumbling or hesitating, check all wiring and connectors that lead to the cylinders (i.e. spark plugs). Depending on how long the ignition components have been in the car, it may be a good idea to replace them as part of your regular maintenance schedule. I would suggest spark plugs, spark plug wires, distributor cap, and rotor (if applicable). Otherwise, check the coils (a.k.a. coil packs). In some cases, the catalytic converter has gone bad. If you smell rotten eggs in the exhaust, your cat converter needs to be replaced. I've also heard in other cases the problems were faulty fuel injectors.
Random misfires that jump around from one cylinder to another. The underlying cause is often a lean fuel condition, which may be due to a vacuum leak in the intake manifold or unmetered air getting past the airflow sensor, or an EGR valve that is stuck open.

Jan 11, 2011 | 2004 Acura MDX

1 Answer

I have a 1999 Chevy Astro that is giving me a P0300 trouble code. So far I've replaced the plugs, wires, cap, rotor, coil, fuel filter, air filter, and catalytic converter. I'm still having the...


P0300 Diagnostic Code - Random Misfire
Technical description:--
Random/Multiple Cylinder Misfire Detected:---
Exactly what does this code means:--
Basically this means that the the car's computer has detected that not all of the engine's cylinders are firing properly.
A P0300 diagnostic code indicates a random or multiple misfire. If the last digit is a number other than zero, it corresponds to the cylinder number that is misfiring. A P0302 code, for example, would tell you cylinder number two is misfiring. Unfortunately, a P0300 doesn't tell you specifically which cylinder(s) is/are mis-firing, nor why.
Symptoms:--
the engine may be harder to start.the engine may stumble / stumble, and/or hesitate.
other symptoms may also be present…There may be rough idle, sputters and stallsand jerks.
Causes:--
A code P0300 may mean that one or more of the following has happened:
Faulty spark plugs or wires, Faulty coil (pack), Faulty oxygen sensor(s)
Faulty fuel injector(s),Burned exhaust valve, Faulty catalytic converter(s)
Stuck/blocked EGR valve / passages, Faulty camshaft position sensor, Defective computer.
Possible solutions for this error problem:--
If there are no symptoms, the simplest thing to do is to reset the code and see if it comes back.
If there are symptoms such as the engine is stumbling or hesitating, check all wiring and connectors that lead to the cylinders (i.e. spark plugs). Depending on how long the ignition components have been in the vehicle, it may be a good idea to replace them as part of your regular maintenance schedule. I would suggest spark plugs, spark plug wires, distributor cap, and rotor (if applicable). Otherwise, check the coils (a.k.a. coil packs). In some cases, the catalytic converter has gone bad. If you smell rotten eggs in the exhaust, your cat converter needs to be replaced. I've also heard in other cases the problems were faulty fuel injectors.
Random misfires that jump around from one cylinder to another (read: P030x codes) also will set a P0300 code. The underlying cause is often a lean fuel condition, which may be due to a vacuum leak in the intake manifold or un-metered air getting past the airflow sensor, or an EGR valve that is stuck open.

Aug 26, 2010 | 1999 Chevrolet Astro

2 Answers

03 chevy express 6.0 misfire code po300, rough idle, sputters and stalls.


P0300 Diagnostic Code - Random Misfire
Technical description:--
Random/Multiple Cylinder Misfire Detected:---
Exactly what does this code means:--
Basically this means that the the car's computer has detected that not all of the engine's cylinders are firing properly.
A P0300 diagnostic code indicates a random or multiple misfire. If the last digit is a number other than zero, it corresponds to the cylinder number that is misfiring. A P0302 code, for example, would tell you cylinder number two is misfiring. Unfortunately, a P0300 doesn't tell you specifically which cylinder(s) is/are mis-firing, nor why.
Symptoms:--
the engine may be harder to start.the engine may stumble / stumble, and/or hesitate.
other symptoms may also be present…There may be rough idle, sputters and stalls and jerks.
Causes:--
A code P0300 may mean that one or more of the following has happened:
Faulty spark plugs or wires, Faulty coil (pack), Faulty oxygen sensor(s)
Faulty fuel injector(s),Burned exhaust valve, Faulty catalytic converter(s)
Stuck/blocked EGR valve / passages, Faulty camshaft position sensor, Defective computer.
Possible solutions for this error problem:--
If there are no symptoms, the simplest thing to do is to reset the code and see if it comes back.
If there are symptoms such as the engine is stumbling or hesitating, check all wiring and connectors that lead to the cylinders (i.e. spark plugs). Depending on how long the ignition components have been in the vehicle, it may be a good idea to replace them as part of your regular maintenance schedule. I would suggest spark plugs, spark plug wires, distributor cap, and rotor (if applicable). Otherwise, check the coils (a.k.a. coil packs). In some cases, the catalytic converter has gone bad. If you smell rotten eggs in the exhaust, your cat converter needs to be replaced. I've also heard in other cases the problems were faulty fuel injectors.
Random misfires that jump around from one cylinder to another (read: P030x codes) also will set a P0300 code. The underlying cause is often a lean fuel condition, which may be due to a vacuum leak in the intake manifold or un-metered air getting past the airflow sensor, or an EGR valve that is stuck open.
Thanks. Keep updated for any more query. You can rate this solution and show your appreciation.

Aug 10, 2010 | 2005 Chevrolet Express

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