2003 Yukon stalls while towing

[ricrog]

OK, I hope someone here has experienced a similar problem although I couldn't find a post reflecting this problem.

We have a 2003 Yukon 5.3 liter V8. It has the towing package (I don't know what the gear ratio is on the tranny) and we were towing a 5,000lb travel trailer last week on vacation. Here is what happened...

About 9 hours into the trip, I was in traffic in Knoxville and as I was accelerating to get through traffic, the check engine light started flashing indicating an engine misfire. I slowed down and the light stopped flashing. This happened one more time in the next few minutes then the engine simply stalled. I pulled to the shoulder and noticed the truck was rough idling then simply died. It wouldn't restart until I waited about 5-10 minutes. Then it fired right up and drove fine. I drove 2 more hours with no problem at all.

On the next leg of the trip, the engine stalled two more times but the check engine light didn't flash. Again, waiting 5-10 minutes and the truck would restart.

After we arrived at the campground and unhooked the camper, I took the truck to a dealer in Charleston and they couldn't find any problem (other than the error code from the misfire over 500 miles before). I drove the truck the remainder of the vacation with no problem but...

On the way home, the first half of the trip went fine. I towed the trailer over 500 miles with no problem. The next day as I was driving, it stalled again. Then it started...I could always wait 5-10 minutes and it would restart fine but the moment I started pulling up a hill or putting any load on it, it would stall. The last half of our trip (300 miles) took over 6 hours. I'd say it stalled 15 times. I tried to baby it by not driving over 50mph all to no avail. Any time it started to put the engine under strain, it would stall. The check engine light never did flash again.

We just bought this truck from a used car dealer so I don't really have a warranty to speak of.

Any ideas? Originally, it seemed to happen only when I was below 1/4 tank of gas, but near the end, it didn't really matter...it would stall regardless of how much fuel was in the tank. It does seem to be related to heat but I really don't know. Fuel pump? Ignition module? There seems to be a little bit of logic to either one, but I'm just not sure and don't want to spend too much money "guessing". I've seen too many posts out here where people have taken their problems to the dealer and they leave with a big fat question mark over their heads.

I appreciate all of your help. I trust the answer is out there somewhere!

Rich

[fortcarp]

Try giving throttle body a good cleaning. You may have to remove it and clean the back side too.