My parents have a 2001 express with the 5.7. The issue is that it will die on idle. It will start fine and idles fine but once you start driving it will die at stop lights. Sometimes it runs flawlessly though. Others it will die as soon as its put in gear. There are no codes or lights being thrown out. In recent times it has had a new alt and battery, full tune up, had the rear ac worked on by the dealer, then the issue started. We then had the fuel pump and fuel filter replaced but still no go. It has about 110k. Any help would be great. All work haas been done by a local mechanic and he can't figure it out.

 

does this happen all the time weather it's cold or hot out?

 

could be something as basic as bad plug wire connections, if the problem came about after a tune-up, i would be looking at what was done, plug wire connections get loose after being repetedly taken off and put back on, also use di-electric grease

 

Hi, my 99 express did something similar a couple of months after I had done a complete tune up. The van died and had to have it towed. The diagnosis: bad distributor cap and rotor. And I had replaced them with brand new AZ parts! I don't know if the 01 uses the same system, but it's a suggestion. Good luck.

 

The cold weather was originally a theory of mine but it did not pan out. It does it randomly.

 

**UPDATE** My dad decided to mess with it the other day and here is what happened. I told him it might be the MAF and had him clean it out but had no luck. he van sat for a few weeks and he decided to mess with it one day. He started the van and it was running rough. He decided to unplug both wire on the MAF. It immediately started to run better. He took it out the the country and it ran fine but had no power. He decided to plug one of the two wire back in and he got his power back and still ran fine. When he got home he plugged in the second one and so far it is still running fine. He is going to replace the MAF and we will see what happens. That all does make sense but still odd. Anyone have input?

 

well my old truck (95 k1500) ran rough all the time (especially in cold weather) after tinkering with everything after changing the EGR it ran a lot better, still a bit rough but a lot better than it was