Rough Running

2002 Yukon XL 5.3 43.000 miles

Problem: start car - engine idles rough. have to "play" with gas pedal to drive slowly through parking lot - feels like it will stall out.
Put the hammer down, and after a second of rough acceleration, the thing "unclogs" and goes great. Doesn't seem to have a problem until the next time it is started.

I drove 300 miles, shut off the car for maybe 20 minutes, then when I started it up this happened for the first time about a week ago.
It was fine for a day or two. Now, it seems like every time I start it, this happens.

I drove 600 miles yesterday pulling a trailer and had no problems except when I stopped at Wendy's for a few minutes and started it up to leave.

Any suggestions will be thoughtfully considered.
Thanks, Bill

More problems today.
I drove 15 miles just fine.
Parked for 20 minutes. Started up fine, but when I pulled out into traffic, I got sputtering and spitting.
The "service engine" light came on for about 30 seconds.
The car accelerated very slowly with the pedal down pretty far.
After less than a mile, the car ran fine again.
(the tank is full)

I had to take it to the dealership.
The problem was getting worse every day.
They said the retreived a " misfire " code.
They determined it needed a fuel filter, fuel injector cleaner, and the throttle body removed and a new gasket installed to cure a vacuum leak.
Well, 18 miles after picking it up, the problem is happening again. I will be in touch with the dealership first thing Monday.

By the way, the cost of repairs totalled $560.xx.
Feels good to throw money away!

You know, once when I failed to lock my gas cap similar things happened to my Yukon.

Yeah, I checked that after reading these forums.
It has happened over several fill-ups now.
It is going back into the dealership tonight.
The problems are exactly the same as before all the work they did last week.

Hi, all things done are reasonable, the cost is another story. You get used to that...
There just must be something else not found yet.
Could it have to do with the engine warmup cycle?
There are so many sensors and computers...
Take care, Eggert :bananasmi

I dropped it off tonight for a "first thing in the morning" appt. The service writer said some "stuff" could have been loosened up in the fuel system when they worked on the rails. He said it was not uncommon to continue replacing things until everything is new. (at my expense)
My point is: They had it for 2 days, found the stored codes, cleaned/repaired what they thought was nessesary,road tested it, 2 people signed off on it as being fixed before I picked it up.
Now, is this visit going to be covered under the warranty on my invoice? The service writer says probably not, made me sign for a $85 diagnostic fee (included last week as well).
-Bill

Hi Bill,
you should be frosted, just be nice and persistent in that they did fix it and now have to fix the fix.
Forget about the service writer and talk to the service manager, and if necessary, the zone manager and ask for a free goodwill repair.

Take care, Eggert :bananasmi

Now they tell me I need to replace 2 of the injectors at a cost of $371.
Not covered under their gaurantee because they did not work on those the first time it was in.
Any idea how to contact the Zone Manager?

Hi, bubble it up through the service manager.
You should be able to get some sort of arrangement.
Take care, Eggert :bananasmi

Hey man, sorry to hear of your problems. I had a similar problem as you stated. Actually, I had the same problem with the dealer on another issue. I took it in to get something fixed (an exhaust rattle) and they claimed it was the muffler straps that were loose and that it would cost me $120 to get new straps installed. OK. They installed the straps and away I went. As soon as I was pulling out of the drive, The rattle was back. I immediately pulled back in and took the auto tech for a ride to let him hear the rattle. We pulled back in and put the Yuke on the lift and the tech actually found the problem this time (shot muffler). So, the service rep gleefully walks up to me and proceeds to inform the that the cost of a new muffler will be $745.00.

As you can imagine I about shit my pants.

I told him he can forget it, that I will go to a custom muffler shop and have a dual system bent for less than half that price. I then ask him "What about my $120.00?". At this point he looks confused. I then stated (in my loud [Mr. Serious] voice in front of customers) that he charged me 120 bucks for something that he didnt fix.

3 days later I had a check in the mail.

Now, as far as the "rough"condition with the idle... I had that too. I just went to Autozone and picked up a can of Throttle body cleaner. Its very important that you get throttle body cleaner and not the standard carb cleaner. I proceeded to pull of my whole intake. I sprayed down the resistors on the MAF sensor and noticed that there was a fair amount of carbon built up on the bottom of the throttle body not allowing a good closure for the blade. I cleaned all of that out. After putting Humpty Dumpty back together again, it ran smooth as can be. Hasnt stumbled since.

Good luck :)

Had the two injectors replaced. They claim I put contaminated gas in that clogged up all the above mentioned parts. Next day, same problem.
Took it back for another days worth of diagnosis, this time they let some experienced look at it.
Turns out, there was a bad electrical connectin on Bank 2 O2 sensor and he replaced the short wire harness also. Working great so far!! Oh yeah, no charge for the third and hopefully final visit.
Question: How much would the third repair have cost me if it were the first? It seems to me that the actual problem had nothing to do with bad gas that I put in the tank. I ended up shelling out around $670.00.