Hi, I have trouble to identify the problem with my 1994 chevy caprice, 5.7L engine.
Under load, after engine heated up: hesitate when accelerating, do not respond to rapid press on accelerator (feels like fuel starving)
, when accelerating sometimes a back fire like noise, when cruising whenever load is increased (eg. slight up hill) feels like intermittent missing.
The yellow light signal "engine need service soon" is not on, neither any other warning lights.
Car starts, idle as well as rev up perfect under no load..
New spark plugs, air filter, and inline fuel filter.
Fuel pressure normal and steady at idle and higher rpm's. (tested while the car is parked)
Tried new MAF and MAP sensors, no improvement.
Any idea?? Thanks, Thad

Thad, it could be a few things that came to mind.....water in the fuel/ vacuum leak at intake/ timing being off/ or a bad valve, try some injector cleaner, and do a vacuum test on the engine/ also check the timing.

Spark plug wires an "break up" / misfire under a load..



Just an added thought.



Jim


(This post was edited by JIM N on Jun 13, 2008, 1:10 AM)