'89 350 TBI Problems

Just bought an '89 1500 2 wheel drive, The truck is back firing, sputtering and lacks pwr while the truck is moving. It will Idle smooth and rev up fine while in park. Will even rev up while under load on the shop floor but when taken on road test is runs as mentioned. We have replaced the distrubitor, tested all sensors, set timing to 0 deg., replaced the plugs, wires, cap, rotor, coil, even took the cat off to see if that was blocked up but still have the problem. This one has me baffled. Any help would be awsome.

Btw great forum

Well, since you have changed all the electrical components, then I would try a fuel filter. They are only like $10 at Advanced. If the filter is dirty then it would cause it to lack power and not run great. Could also be maybe a bad Injector. This would definetly account for lack of power and missing, but I'm not sure about the backfiring part. Hope that helps.

try running the truck with the breather off and manually inspecting the fuel injectors. I had a similar pronblem with my 4.3l TBI One of the fuel injector connectors was getting worn and would loosen occassionally from normal vibration. In essence, when this happened one of the injectors stopped "firing" and the truck would start starving for fuel. And like you said, it only happened on-the-road.
Also, the same problem can happen with the clogged fuel filter mentioned by CT92

GL!

Thanks guys, I will give it a try today and let you know what I come up with

try tapping the computer sometimes they get sensitive to vibrations

I got it fixed, Had to rebuild the throttle body and replaced the fuel filter. Thanks to everyone for their help. :cool: