Help/advise needed on 94 Chevy 5.7 - 350

[Gleason]

Hey guys,

I need some help in troubleshooting what's wrong with my 94 chevy truck,automatic trans. 4wd, 150k. About a week ago, towing the boat back from the lake, I barely thought I'd get home with her........stalled at stop signs, had no power to climb hills and would hesitate and miss around 30-40 mile an hour.I'd depress the gas peddle down further and the engine would'nt respond for maybe 3 seconds or so and then all the sudden she'd snap out of it and be screaming along because I had my foot to the floor.

My first thought was, I hope someone did'nt put something in my tank at the boat landing. I've never experienced bad or contaminated gas, but that's what it seemed like. I changed plugs, wires, rotor, distributer cap air filter and fuel filter, added some Iso Heat and sea foam and though it does run much better; it still is'nt right. If I sit at a stop sign in gear for anymore than a minute, it starts idleing down and gasping for it's life. Since leaving the boat landing and all the this trouble, I've filled the tank only once with new gas, so perhaps I may still have some bad gas in the system. She seems to run fine "cold" and going down the highway and climbing hills again, but does'nt idle right in gear at a complete stop after she's warmed up. Maybe I'm just paranoid, but could I have a fuel pump issue or injectors about to go bad?

Any advice or experience with something like this would be much appreciated!

[Big Buck Buster]

Try cleaning out the throttle housing with a good carb cleaner.

I would also try unplugging the vacuum line from the EGR, then drive it. If it goes away with the vacuum unplugged from the EGR, replace the EGR.

[Esox_Magnum]

Did you also change the fuel filter? We had a work truck do something similar once and that was the problem.

[Kodiak]

fuel pump garuntee it.

[Kodiak]

gm's eat fuel pumps, when you replace it make sure you purchase a delco pump and not an airtex. the airtex cost about 279 and the delco is like 360 i bet,,but the airtex last like a year or so.... this is a well known gm issue, they eat fuel pumps....and just as essox said try the fuel filter first but if it does not work it is the pump...and when you replace the pump replace the fuel filter. Clean your maf and airbox too.

[Jeremy airjer W]

Is the check engine light on?

[Big Buck Buster]

He already changed the fuel filter.

[Gleason]

I GOTTER!!

Thanks for the help guys. Big Buck Buster, you were pretty close. I was actually carb cleaning out in/around the throttle housing when it dawned on me to unscrew the IAC (Idle Air Control Valve) and check it for carbon build up and see if the spring was o.k or broken. Totally carboned/gunked up! 10 minute fix that had me about ready to sell the truck and say "good riddens"! Idle's beautifully in gear as well as park and neutral now.

[Big Buck Buster]

Sometimes I get lucky when cleaning the throttle housing out with the IAC pintle. I usually shoot the carb spray down in the IAC intake and try to clean it out before I remove it. It works sometimes.