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help! engine miss

2307 Views 4 Replies 3 Participants Last post by  lrrymrtn
please help! i love my '07 yukon. a couple of months ago i noticed a miss/hesitation in the engine. i took it to my dealer, they told me i had contaminated fuel. doesnt look right or smell right. i cant hardly believe this, its brand new. i get gas at the same station for all my cars/trucks. none of them have any problem. i go for second opinion. this dealer says no trouble found. gives me a tsb that applies to the 6.0, mine has 5.3 that says this is normal due to stiffer engine mounts etc. i feel as though they didnt want to fool with it either. my buddys brother works at yet another gmc dealer, him and his buddies in the serv. dept. laughed because my dealer wanted to charge me to fix @ $70/hr for 4-5 hrs. to drop tank clean tank pull fuel lines clean everything out. now mind you they dont know exactly what is in tank because they have not looked. they are just guessing until they pull it apart. 30rd dealer didnt fix it either by the way. my gripe is i have a brand new truck that runs like crap and i cant get it fixed. i just dont buy the bad gas thing. i've run several tanks of premium gas and even tried fuel system additives. nothing helps. i'm to my witts end.
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Just a guess, because we have no idea where you live.

Water in the gas, try some dry gas.

It could also be,

A bad plug,

A bad plug wire,
I know this is an 07 and shouldn’t have bad parts, but when I worked at the factory we were asked to drive new ones home every once in a while.

You wouldn’t believe the things that broke or failed on cars with 0 miles on them.

Radiater hoses,

Plug wires,


All brand new.

I just replaced plug wires myself yesterday that had a lifetime warranty that made the truck skip after it warmed up. They were less that a year old.
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Trouble codes?

Are there any DTC codes? P301, 302, 303 etc are misfire codes related to specific cylinders. If you have a fuel contamination issue, you would likely see a low pressure. Pull the filter yourself and see if it will pass air. Note: If you do take it to the dealer, make sure that you have the service writer indicate that you are bringing the truck in for diagnosis of a misfire. Don't agree to replace/repair any component unless they guaranty that it will fix the 'misfire.' That way if you shell out $400 for tank/line cleaning and the problem is still there.......busted! If they won't guaranty their diagnosis, get the heck out of there.

P.S. 3 times back to the dealer for the same problem and the lemon law will get you a refund.
nope, no codes. i mentioned checking pressure, checking fuel filter, etc. they said the '07 has a non servicable filter? i just wanted to be sure before i took action with the lemon law or something. i've tried contacting GM not much help there either. everybody i've talked to seems to think if were actually bad gas it should have worked its way out by now. the dealer seems to be suggesting that something is actually contaminating the tank, some type of foreign object. i just dont buy it. i mean i could be wrong, i just dont buy it. my company truck is ford f-series. i'm real good friends with one of the senior mechanics at the local ford dealer, the other day i went to pick up my ford and i said hey come out here and check this out. he got in sat down , rev it up, put in gear, held brake and push the gas, then told me if it was mine theyd fix it. dont believe its in the gas. maybe int the ignition or something like that. its been doing it for sometime now. my wife and daughter drive the stuoid thing, i dont want them to get hurt. you know when you go to pull out in traffic it hesitates.
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