350 TBI STUMBLES/MISFIRES ?????

[oldskool]

I have been searching old threads on this forum and looking at all kinds of web sites trying to find and answer to my trucks problem.

'95 GMC Sierra SLT ex-cab step side. 5.7 TBI, 4L60E, 3.42 posi.
360 000 km, rebuilt trans.

REPLACED: plugs, wires, cap and rotor. replaced IAC, pulled distributor and inspected. Timing is ok.

When the truck is cold it runs fine, once I have a temp reading on the dash and come to my next stop, I can feel the engine shake/misfire? If I'm at a slow speed just off idle (the coffee shop drive thru) it stumbles until I can get back up to speed. When I let off the throttle at low rpm it almost stalls and catches it self back up. Have cleaned the tbi and all sensors. Have cleaned and checked the egr. Money is limited and any help or advice on how to correct this would be greatly appreciated.

I intend to keep this truck for a while, as I am collecting the parts to do a full air ride and more...

 

[DRAGGIN95]

Hello, I have a couple of ideas, first I didn't see where you said you had changed the fuel filter recently, if not definitly change it, and also you may need to pull the sending unit out of the fuel tank and inspect the sock/filter on the pump itself. Second, I have rebuilt prob. 10 of these throttle bodies, you said you cleaned it, but did you rebuild it, I can get a rebuild kit from O'reilly's here locally for about $40 and it makes a world of difference, also this kit includes the tiny little filter's that are located on the side of the actual injector's. There is also a chance that it could be your ignition module in the distributor, because when they get old and the original heat sink compound goes dry, they get much more succeptible to heat, and as the truck warm's up it start's running poorly. Good luck and I hope you find the problem.

 

[oldskool]

I have replaced the fuel filter back in the spring when I bought the truck, although with the junky gas at the pumps it may need a fresh one. I have been debating on rebuilding the throttle body. The ignition module is a good possibility considering the mileage I have on this truck. Will try these corrections and see what happens. Thanx.

 

[94 Silverado]

I vote for the distributor module as well. It's pretty cheap and probably needs a new one anyway even if that's not it.