Question about 2003 GMC Yukon XL

2 Answers

I have a 2003 gmc yukon, i have misfires on1,3,5 and 7 cyclinders mainly on 1 and 7. i've replaced spark plugs,wires and cam shaft position sencor. i've check fuel presure and it was fine, checked fuel injectors and they works. there is fire at each coil pack. can anyone help?

Posted by ed3strader on


2 Answers

Frank Meert

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points


    An expert that got 10 achievements.


    An expert that got 5 achievements.

    Vice President:

    An expert whose answer got voted for 100 times.

  • Master
  • 610 Answers

Get back to basics. pull the plugs and check your compression. If ok, I would listen to injectors with a stethocope, and check resistance of injectors against spec..

Posted on Oct 01, 2011

  • Frank Meert Oct 01, 2011

    Also check for cat converter restiction on the drivers side, as you have a miss on 1,3,5,7 which are on the driver's side.




  • Level 2:

    An expert who has achieved level 2 by getting 100 points


    An expert who has answered 20 questions.


    An expert that has over 10 points.


    An expert whose answer got voted for 2 times.

  • Expert
  • 33 Answers

Either a new clutch or timeing belt. hopefully the trasmission is ok

Posted on Jun 02, 2009


Add Your Answer

Uploading: 0%


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



Related Questions:

1 Answer

2003 gmc yukon denali has no injector pulse and no spark

Check for engine rpm signal, sounds like a cam/crank shaft position sensor issue.

Nov 08, 2012 | 2003 GMC Yukon Denali

1 Answer

I got a tune up today on my Yukon which they only replaced 4 wires & all the plugs. the dealership says cyclinders 1&3 where misfiring. my truck runs better but stil vibrates. what could it be?

I would replace the other 4 wires and see if it's better. If so ask why they only replaced 4. Makes no sense. They should have been able to hook up a scope and see the ignition pattern, if all was well, they should have checked compression, and injector performance.

Sep 29, 2011 | 2003 GMC Yukon

2 Answers

I got a tune up today on my Yukon which they only replaced 4 wires & all the plugs. the dealership says cyclinders 1&3 where misfiring. my truck runs better but stil vibrates. what could it be?

You should have the dealership replace all of the spark plug wires, not just 4 of them. If the vehicle still vibrates like a misfire you may need to have your timing checked/adjusted. It may also be time for a new fuel filter.

I’m happy to help further over the phone at

Sep 29, 2011 | Cars & Trucks

1 Answer

I have a 2003 yukon Problem with the GMC Yukon XL

What size engine ? 4.3 L vortex P0300 random misfire code is usually associated with vacuum leaks , but could also be low fuel pressure , plugged fuel filter , fuel pump problem , clogged injectors etc... doing fuel pressure an flow testing would confirm or eliminate that as a problem . Fuel injector balance testing would confirm or eliminate clogged injectors .

Mar 24, 2017 | 2003 GMC Yukon XL

1 Answer

I have a 1998 gmc suburban and it is misfire on cyclinder 4 and cyclinder 5 what can it be

IT could be bad spark plug wires or do you have the wires switched?

Sep 14, 2010 | 1998 GMC Suburban

1 Answer

I have a 98 gmc yukon that is misfiring on cyclinder 1.

assume still misfiring?
have u checked the fuel injector????

Apr 16, 2010 | 2003 Volkswagen Beetle TDI

2 Answers

Possible o2 sensor 2002 GMC Onvoy

O2 sensors indicate unburned oxygen in the exhaust sysytem. Bad O2 sensors causes fuel mixture to run rich. It causes fuel consumption and your emmissions test will not pass. Check for vacuum leaks check the manifold.check for a misfiring cylinder, a burned exhaust valve that is leaking compression. replace the O2 sensor or sensors. Some cars have 2 . One for the intake another for the out take. If it reads a code for the Map sensor along with the O2. It is better ifyou replace both sensors. But I think that the problem lies in the oxygen sensor or sensors. Pleae vote my answer if this helps.

Jan 15, 2009 | 2002 GMC Envoy

2 Answers

Misfires on cyclinders

crank shaft sencor cam shaft censor.02 sensor

Jan 15, 2009 | 2000 Honda Accord

Not finding what you are looking for?
2003 GMC Yukon XL Logo

208 people viewed this question

Ask a Question

Usually answered in minutes!

Top GMC Experts


Level 3 Expert

85239 Answers

Colin Stickland
Colin Stickland

Level 3 Expert

22485 Answers

Jeffrey Turcotte
Jeffrey Turcotte

Level 3 Expert

8984 Answers

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

Answer questions

Manuals & User Guides