1991 Chevy Silverado Tune up?

LTDESP

MEMBER
1991 CHEVROLET SILVERADO

Engine Performance problem
1991 Chevy Silverado Four Wheel Drive Manual

Its actually a 1991 K1500 w\ 5.7 L V8. I just bought this truck, and there are lots of custom riggings on this truck. What I am writing about is engine performance. Truck starts fine, idles (a little high) but fine. When you step on the gas to go. It feels like its gasping for fuel, air, or spark? But if you really step on it, it will take off just fine. It does not have close to the power a 350 should have. Im not a speed demon, but it won't reach highway speeds on the on-ramp unless I really punch it. Going uphill is a real struggle. And on long trips, you can feel the engine losing compression. Once you get up to speed it runs fine. But if there is just a small incline, I have to drop it into 4th gear, to get back up to speed. I was told the engine and the manual tranny were almost new when I bought it. And the engine looks pretty new. There is a crack in the exhaust manifold, but Im not sure it would cause poor acceleration. Would it? I just replaced the fuel filter and (no difference.) I ran a fuel cleaner and no change. Next step is plugs and wires. Hopefully you can help me, cause I dont have alot of time to go down the list of possible engine performance fixes. Thanks.

1 Reply

DOCHAGERTY

MECHANIC
9,601 POSTS

As the resident BMW guy, I do not have the magic bullet for your truck, but to start with, I would check the "health" of the engine by checking the compression and for vacuum leaks in the intake system. The exhaust leak needs to be addressed as well. If the tune up specifications are not correct, then they should be adjusted to the factory recommendations. Just replacing the components will not guarantee success, have a plan, follow it through, find out what is wrong before you throw $$ away.