97 Chev 4x4 P.U. 5.7 stumbles & misses

you new fuel pump may not be powerful. it might not give the load needed to power the truck or your timing may be alittle off or even you might have alittle miss fire

thanks dunndunn, But the pump is brand new original equipment, and it solved my no start problem. It can't be the timing, cause it runs fine,but at intermittent times, more so when I use the A/C is when it skips and stumbles, after my speed is up it not as bad. Anyone else got any ideas

If you can get your hands on a real time OBD2 scanner and watch timing. There is a remote chance that it could be a fuel octane issue. When A/C in on it loads engine it does increase octane needs and when ECM detects a knock, it retards spark quickly which can cause erratic engine operation. You could also have a flakey crank postion sensor that is not coding. Again though a real time scanner will track your problem down.

----------------- The SnoMan

Sounds to me like you have moisture in your distributor cap and when it looks for a heavier load it would be looking for that extra fire,, it misses cause of contact.. just some 2 cents to check out.