Question about 1998 GMC Sierra

1 Answer

Vacuum leak changed plugs and wires and rotor cap and cylinder 4 misfires at 80 mph? what can i be?

Posted by on

Ad

1 Answer

  • Level 2:

    An expert who has achieved level 2 by getting 100 points

    MVP:

    An expert that gotĀ 5 achievements.

    Governor:

    An expert whose answer gotĀ voted for 20 times.

    Hot-Shot:

    An expert who has answered 20 questions.

  • Expert
  • 72 Answers

Its possible that you have a burnt or sticking valve if you havent done so yet I would reccomend doing a leak down test on #4 to see if it holds compression. I hope this helps you , Good luck !!

Posted on May 10, 2010

Ad

1 Suggested Answer

6ya6ya
  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

Hi,
a 6ya expert can help you resolve that issue over the phone in a minute or two.
best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
the service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need.
goodluck!

Posted on Jan 02, 2017

Ad

Add Your Answer

Uploading: 0%

my-video-file.mp4

Complete. Click "Add" to insert your video. Add

×

Loading...
Loading...

Related Questions:

1 Answer

2001 Blazer rough idle and misfire cylinder 2 code


misfire codes are most often generated by faulty injectors and not what you have replaced
the misfire can be from blocked injector tip, failing injector wiring/signal and low fuel pressure
move the injector for 2 to another cylinder and see if the code moves as well to the next cylinder ( replace injector)
if not check wiring or ECM for problems

Jan 30, 2016 | 2001 Chevrolet Blazer

2 Answers

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

Jun 12, 2014 | 1998 Chevrolet Tahoe

3 Answers

Cylinder misfire p0300


START THE ENGINE AND LIFT THE IGNITION WIRE LISTEN FOR SPARKS.IF ONE OR MORE CYLINDERS DON'T CHANGE THE WAY IS RUNNING ,YOU GOT THE BAD CYLINDER. LOOK FOR BURN MARKS ON THE WIRE(BLUE/WHITE SPOT)IF SO REPLACE THE WIRE.SOME TIMES VALVE COVER LEAKING IN THE TUBE. REPLACE VALVE COVER GASKET,BLOW THE OIL OUT BEFORE REMOVE THE SPARK PLUGS.REMOVE THE SPARK PLUGS AND INSPECT THE ELECTRODE.GOOD ELECTRODE WILL BE WITH SHARP EDGE ,IF ROUND OR LIKE CONE REPLACE WITH DENSO OR NGK ORIGINAL EQUIPMENT . REMOVE THE DISTRIBUTOR CAP AND LOOK FOR OIL IN THE CAP. IF OIL INSIDE REPLACE DISTRIBUTOR. IF NO OIL INSPECT THE CAP AND ROTOR FOR THICK WHITE DEPOSIT OR ROTOR FOR BLACK BURN MARKS. REPLACE CAP AND ROTOR.IF EL.SYSTEM IS OK SPRAY CARB CLEANER ON INTAKE MANIFOLD AND LISTEN FOR RPM CHANGE.IF CHANGE THE RPM REPLACE MANIFOLD GASKET.

Mar 29, 2014 | 1998 Acura Integra Type R

1 Answer

1998 nissan frontier xe 4 cyl auto misfire cyl #2 engine vibrates like a bad sparkplug when driving


To review - - do you know for a fact the distributor is firing that cylinder? And do you have power and a ground pulse for that injector ?
You say no vac leak, but have you done a compression test on all cylinders ? Is it possible the egr valve is leaking and affecting that cylinder ?

Feb 20, 2014 | Nissan Cars & Trucks

1 Answer

I am working on a 1998 honda accord ex 4 cylinder. it keeps throwing a miss fire code for all cylinders when you get on it at about 60 mph and won't accelerate past this until you let off and hit


Hi there:
First I suggest scanned the ECU. The misfire counter function can help you determine which cylinder is behaving badly. Clearly this is not an option for all people and vehicles though.
NOTE: Even without engine scanners you can identify which cylinder is causing a dead misfire. Carefully disconnect one spark plug at a time. If the cylinder you are disconnecting is operating properly you will hear a change in RPM. If the cylinder you disabled is the bad cylinder you will see no change in engine behavior.

Check your ignition system. There are several steps to this.
- Remove spark plugs and check to see if the electrodes look worn down or contaminated. Check your spark plug gap with a plug gapper to see if the electrode has worn down.
- Use a multimeter to check your spark plug wire resistance. They should read roughly between 2,000 - 12,000 Ohms. What you are really looking for is an open circuit in one of the wires. Bend the wires around and see if you lose continuity.
- Check cap and Rotor. Look for carbon tracking or extremely worn down rotor.
- On newer vehicles with distributeless ignition systems coils are prone to failure. If you know which cylinder is misfiring try swapping that cylinder's ignition coil with another cylinder and see if the misfire moves with it.

If you know your ignition system is operating properly you may want to check compression. You may already have the spark plugs out from your ignition check so it only takes a minute to check engine compression.

Fuel injection Service - The motorvac service works miracles. It is available at most repair facillities. Adding a can of fuel injector cleaner to your fuel tank is not ecnough to clean out a severely plugged injector. The motorvac solvent is much more potent and should only be used with a fuel injection cleaning machine. It is a good place to check with a hard to find misfire.

Vacuum leaks - A vacuum leak will cause a misfire. If the leak is near a certain cylinder that cylinder will misfire. You can try to find a leak by spraying down the engine carefully with carb cleaner. If you spray the location of the leak the RPMs will rise. You can also inject the intake manifold with smoke from a smoke machine and look to see if it leaks out anywhere it is not supposed to.

Hope this helps; also keep in mind that your feedback is important and I`ll appreciate your time and consideration if you leave some testimonial comment about this answer.

Thank you for using FixYa, have a nice day.

Feb 17, 2012 | 1998 Honda Accord

1 Answer

1998 honda accord ex is missing on all 4 cylinders. how to fix


Hi John:
First I suggest scanned the ECU. The misfire counter function can help you determine which cylinder is behaving badly. Clearly this is not an option for all people and vehicles though.
NOTE: Even without engine scanners you can identify which cylinder is causing a dead misfire. Carefully disconnect one spark plug at a time. If the cylinder you are disconnecting is operating properly you will hear a change in RPM. If the cylinder you disabled is the bad cylinder you will see no change in engine behavior.

Check your ignition system. There are several steps to this.
- Remove spark plugs and check to see if the electrodes look worn down or contaminated. Check your spark plug gap with a plug gapper to see if the electrode has worn down.
- Use a multimeter to check your spark plug wire resistance. They should read roughly between 2,000 - 12,000 Ohms. What you are really looking for is an open circuit in one of the wires. Bend the wires around and see if you lose continuity.
- Check cap and Rotor. Look for carbon tracking or extremely worn down rotor.
- On newer vehicles with distributeless ignition systems coils are prone to failure. If you know which cylinder is misfiring try swapping that cylinder's ignition coil with another cylinder and see if the misfire moves with it.

If you know your ignition system is operating properly you may want to check compression. You may already have the spark plugs out from your ignition check so it only takes a minute to check engine compression.

Fuel injection Service - The motorvac service works miracles. It is available at most repair facillities. Adding a can of fuel injector cleaner to your fuel tank is not ecnough to clean out a severely plugged injector. The motorvac solvent is much more potent and should only be used with a fuel injection cleaning machine. It is a good place to check with a hard to find misfire.

Vacuum leaks - A vacuum leak will cause a misfire. If the leak is near a certain cylinder that cylinder will misfire. You can try to find a leak by spraying down the engine carefully with carb cleaner. If you spray the location of the leak the RPMs will rise. You can also inject the intake manifold with smoke from a smoke machine and look to see if it leaks out anywhere it is not supposed to.

Hope this helps; also keep in mind that your feedback is important and I`ll appreciate your time and consideration if you leave some testimonial comment about this answer.

Thank you for using FixYa, have a nice day

Feb 17, 2012 | 1998 Honda Accord

1 Answer

What could cause MISFIRE CYLINDER 8. I already


Do a cylinder leakage / leak down test to determine if the valves and seals are leaking.

Apr 02, 2010 | 1997 Dodge Dakota

Not finding what you are looking for?
1998 GMC Sierra Logo

Related Topics:

56 people viewed this question

Ask a Question

Usually answered in minutes!

Top GMC Experts

yadayada
yadayada

Level 3 Expert

76164 Answers

Freddy

Level 3 Expert

1311 Answers

Colin Stickland
Colin Stickland

Level 3 Expert

22156 Answers

Are you a GMC Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides

Loading...