How do I find my misfire?

2,335

Asked by Jeff Oct 31, 2022 at 11:36 AM about the 2003 GMC Yukon Base

Question type: Maintenance & Repair

I have a 2003 GMC Yukon. I have misfires on 1,3,5,&7. I have good
compression, spark, and injector pulse. I checked injector balance and all
injectors flow the same. It has a 4.8 V8. Can anyone tell me what to check
next?

3 Answers

310,565

All misfires on the same bank of cylinders, so it is something common to all of them on that side, internal vacuum leak, exhaust restriction on that bank, early sign of a blown headgasket, weak ignition driver circuit.

1,930

If you have a code for cat below threshold,and 02 sensor bank 2 the cat is not getting hot enough to keep system fuel trim balanced,once this code is tripped fuel. Trim goes full lean. Causing random misfire. Ls 4.8-6.0 are notorious for intake gaskets those are where where I would start. I had one of these. Tossed reduced engine power tried everything to fix it. No luck junked it.

1 people found this helpful.
2,335

Finally got this one sorted. Back pressure on bank 1 at idle was 8 PSI at idle. Change cat converters and problem was solved.

Your Answer:

Yukon

Looking for a Used Yukon in your area?

CarGurus has 14,326 nationwide Yukon listings starting at $1,899.

ZIP:

Own this car?

Share your experience with others.

2003 GMC Yukon

Review another car

CarGurus Experts

  • #1
    MikeDaGeek
    Reputation
    9,650
  • #2
    clayduster71
    Reputation
    5,220
  • #3
    David Boccabello
    Reputation
    4,030
View All

Know more, shop wisely

Search

Related Models For Sale

Used Chevrolet Tahoe
1,428 Great Deals out of 32,545 listings starting at $1,550
Used Cadillac Escalade
359 Great Deals out of 8,709 listings starting at $3,900
Used GMC Yukon XL
468 Great Deals out of 11,721 listings starting at $2,934
Used GMC Sierra 1500
2,007 Great Deals out of 72,192 listings starting at $1,900
Used Chevrolet Suburban
647 Great Deals out of 16,989 listings starting at $1,599
Used Ford Expedition
1,098 Great Deals out of 36,876 listings starting at $500
Used Chevrolet Silverado 1500
4,409 Great Deals out of 123,453 listings starting at $1,995
Used Toyota Sequoia
140 Great Deals out of 3,283 listings starting at $3,900
Used Ford F-150
6,819 Great Deals out of 174,976 listings starting at $1,995
Used GMC Sierra 2500HD
551 Great Deals out of 23,677 listings starting at $3,995
Used Lexus GX
245 Great Deals out of 4,524 listings starting at $3,999
Used Lincoln Navigator
236 Great Deals out of 9,800 listings starting at $1,000
Used Dodge Durango
851 Great Deals out of 21,274 listings starting at $850

Used Cars for Sale

2024 GMC Yukon For Sale
30 Great Deals out of 2,937 listings starting at $54,169
2023 GMC Yukon For Sale
118 Great Deals out of 1,251 listings starting at $43,291
2022 GMC Yukon For Sale
98 Great Deals out of 857 listings starting at $34,876
2021 GMC Yukon For Sale
113 Great Deals out of 1,384 listings starting at $32,491
2020 GMC Yukon For Sale
37 Great Deals out of 457 listings starting at $19,944

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use. Content will be removed if CarGurus becomes aware that it violates our policies.