Question about 1998 GMC Sierra

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My check engine is on and the code reader says its a random multipe misfire, and misfire on cylinder 4. ive changed the plugs and wires and cleared the codes and the same ones came back on. theres also a code that says the rpm's are higher than expected dont know if its related.

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Have you checked the coil pack for cyl 4? are you getting spark? it could be grounding out somewhere check your cables for carbon

Posted on Aug 06, 2010

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Nov 28, 2015 | Cars & Trucks

1 Answer

2003 sorento 3.5 cranks won't start code 300 302 304 306


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Feb 17, 2015 | 2003 Kia Sorento

1 Answer

Missing,viborating


Misfire could be a number of things:
a) spark plugs - change them if used over 15K miles - inspect/regap.
b) spark plug wires - change them if over 15K miles - inspect
c) ECM (electronic control module) - test with HEI (high energy ignition) tester.

The vibrating tells me that the engine is running on less than its normal compliment of cylinders - the shaking is produced by the imbalance caused in the engine by one (or more) cylinder(s)
not firing at all.

The "Check Engine" light probably is coming on due the the misfire condition. Go to Pep Boys or
Advance Auto Pats, where they'll tell you (free) your codes causing the "Check Engine' light to be
lit - the code coming from your truck's computer will probably be one or more of:
P0300 - Random/Multiple Cylinder misfire detected
P0301 - Cylinder 1 misfire detected
P0302 - Cylinder 2 misfire detected
P0303 - Cylinder 3 misfire detected
P0304 - Cylinder 4 misfire detected
P0305 - Cylinder 5 misfire detected
P0306 - Cylinder 6 misfire detected
P0307 - Cylinder 7 misfire detected
P0308 - Cylinder 8 misfire detected
P0313 - Misfire detected with low fuel

Jun 23, 2011 | 2009 Ford F-150

1 Answer

Vehicle missing,shaking,engine light comes on


Misfire could be a number of things:
a) spark plugs - change them if used over 15K miles - inspect/regap.
b) spark plug wires - change them if over 15K miles - inspect
c) ECM (electronic control module) - test with HEI (high energy ignition) tester.

The shaking tells me that the engine is running on less than its normal compliment of cylinders - the shaking is produced by the imbalance caused in the engine by one (or more) cylinder(s)
not firing at all.

The "Check Engine" light probably is coming on due the the misfire condition. Go to Pep Boys or
Advance Auto Pats, where they'll tell you (free) your codes causing the "Check Engine' light to be
lit - the code coming from your truck's computer will probably be one or more of:
P0300 - Random/Multiple Cylinder misfire detected
P0301 - Cylinder 1 misfire detected
P0302 - Cylinder 2 misfire detected
P0303 - Cylinder 3 misfire detected
P0304 - Cylinder 4 misfire detected
P0305 - Cylinder 5 misfire detected
P0306 - Cylinder 6 misfire detected
P0307 - Cylinder 7 misfire detected
P0308 - Cylinder 8 misfire detected
P0313 - Misfire detected with low fuel

Jun 23, 2011 | 2004 Ford F150

2 Answers

Cylinder 5 and im also getting p0507 idle is higher then expected. ive change plugs wire cap button cam sensor and distributor. but now its throwing the codes p0300 and p0507 it goes from p0300 to p0305...


po 300 is random/ multible cylinder misfire detected po507 idle system rpm high-- go to this site for the po507 meaning--www.obd-codes.com/p507 === please go to this site for the po300 code---- www.obd-codes.com/p0300

Random/Multiple Cylinder Misfire Detected have a good day !!

Feb 15, 2011 | 1997 GMC Sierra

2 Answers

I have a 2003 trailblazer 4.2L Vortec, in line 6 with 250,000 miles. It started running rough with power loss. The code reader showed a misfire in clinder 2. Replaced the coilpak with no luck. The reader...


P0300 - Random/Multiple Cylinder Misfire Detected

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 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 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.


About the your previous code (P0301), this code will trigger the check engine light as follows:

The misfire detection monitor, a software strategy built into the computer, is designed to detect an engine misfire. The computer can also normally identify the specific cylinder in which the misfire has occurred. A misfire is nothing more than a lack of combustion, which can be caused by poor fuel quality or metering, low compression, lack of spark or unmetered air entering the engine. There are other possible, less obvious causes as well, such as uncommanded Exhaust Gas Recirculatin (EGR), flow. When the misfire monitor detects a misfire, it will trigger the check engine light with the specific cylinder number as the last digit in the P030X code. For instance cylinder 1 misfire is P0301, cylinder 2 is P0302 etc.

Possible Causes:
Fuel injectors, related wiring, sensors and computer issues
Running out of gas, or poor fuel quality
Evaporative emissions system (EVAP) concerns: fuel vapors leaking into engine
Incorrect Fuel Pressure
EGR system concerns: leaking EGR valve or restricted ports.
Base engine concerns: low compression, valve train problems and timing issues
Ignition system concerns including, but not limited to:
Faulty spark plugs
Faulty coil or related wiring
Ignition module or related wiring issues
Ignition related sensor faults or wiring issues

Diagnostic Help:
Begin by checking for proper fuel and ignition system operation, and then follow up with the less likely causes listed above, such as EGR and EVAP system problems. New style coil on plug applications have a high failure rate, and can be concluded faulty by swapping to another cylinder and checking to see if the misfire moves to that cylinder. This is a quick check if a capable scan tool or oscilloscope is not available. Always make sure the basic maintenance is done first and that things such as the fuel filter, air filter, spark plugs and spark plug wires are in good working order, as these are all possible candidates for a problem. If necessary, check for wiring and component concerns. See our article "Automotive Circuit Testing 101", if you need more assistance with this. If concern is determined to be intermittent, check out our article on intermittent diagnosis and wiggle test connectors and wiring, attempting to duplicate concern. You may also use the "Get Help" link if you need specifications or have any other related questions. Remember to refer to an appropriate manual for specific instruction.


Keep us updated.

Feb 07, 2011 | Chevrolet TrailBlazer EXT Cars & Trucks

1 Answer

Getting a code P0304 on my 1999 Dodge 1500 5.2L.I changed my spark plugs, wires, cap and rotor about 3-4 mos. ago and have had my check engine lite come on three different times and stay on for 3-4 days at...


the code that is given means that the coil, plug ,plug wires, for that cylinder could be bad, check spark plug and see if this is the problem or a bad wire.

Nov 14, 2009 | Dodge Pickup Cars & Trucks

2 Answers

Engine light came on while driving care on highway after 30 mile. Care was in D3. I'ts a 1997 Acura Integra and the trouble code reads random misfire, cylinder 2 misfire and cylinder 4 misfire.


with out being there to check the spark plugs i would have to say start there. most of the common causes for misfire codes especially randoms are the plugs and wires. good luck

Oct 29, 2009 | Acura Integra Cars & Trucks

1 Answer

Engine light comes on - Code shows P0300 and then


OBD II 300 Random/Multiple Cylinder Misfire Detected

When the misfire monitor detects a misfire, it will trigger the check engine light with the specific cylinder number as the last digit in the P030X code. For instance cylinder 1 misfire is P0301, cylinder 2 is P0302 etc. In this case we have either multiple cylinders misfiring, or the computer simply can't determine the specific cylinder, and as such we are left with the P0300 in computer memory.

Possible Causes:

Fuel injectors, related wiring, sensors and computer issues
Running out of gas, or poor fuel quality
Evaporative emissions system (EVAP) concerns: fuel vapors leaking into engine
Incorrect Fuel Pressure
EGR system concerns: leaking EGR valve or restricted ports
Base engine concerns: low compression, valve train problems and timing issues
Ignition system concerns including, but not limited to:
Faulty spark plugs
Faulty coil or related wiring
Ignition module or related wiring issues
Ignition related sensor faults or wiring issues

Apr 04, 2009 | 1996 Dodge Ram 1500 Club Cab

1 Answer

My 96 jetta has had the same codes for 4 years...help me!!!!


need to know which motor u have, bet its a 2 litre. Get back to me on this, but could likely be the pick up coil which is located in the distributor if it is indeed a 2 litre engine. Maybe mass air flow as well.

Aug 15, 2008 | 1996 Volkswagen Jetta

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