Power loss and backfire 5.7

My friend has a 92 Chevy 1500 and we have replaced his fuel pump, filter, relay, plugs, wires, rotor, cap, throttle body gaskets, pcv valve... and are still having a problem with his truck. It has a major problem with lack of power, and recently has started to backfire more often, usually under load and also tries dying when he gives, or lets off the gas... we replaced his pump and strainer and now his fuel guage works correctly, then he tried starting his truck and it would fire up, so then we replaced his relay, and that fixed the no start, but I cannot figure out what else there is to do. I want to check the resistance for his ignition coil. Does anyone know the specs? I was thinking the timing chain may have slack, but it only runs like crap under load. It seems to idle fine at about 1200 rpm. It's not the catalytic converter because the exhause is snapped before it. There are no engine codes. Any ideas would be appreciated.

have you replaced the o2 sensor? checked spark timing position? if your not pulling any knock codes or anything try advancing the spark a little and also you said that the exaust was missing before the converter? belive it or not the effects of a missing or damaged exaust can be alot greater than most people think esspecially if it is on a motor that is already stugling.

I had similar problem on my 98 Silverado. It would sputter and die, but only under a load - such as climbing a long hill. Otherwise, it ran great. The truck gave out all kinds of different codes, and the dealership was originally stumped. They replaced cap and rotor, then I did wires, fuel filter, etc, etc.

My problem turned out to be the fuel pump. I had the pump replaced by a local shop. But they used a local brand, not OEM. That pump lasted about 2 months, then same sputtering started again. This time, I had the shop use OEM fuel pump and now all is well.

So, I would suggest that you be sure you have a OEM pump in there.

Good luck.

Does anyone know what the resistance of the injectors are supposed to be? TBI.

I found that the impedance is supposed to be between 1 and 2, and that was fine, but afterwards I looked at how the injectors were spraying, and the passanger side was a weak mist, and the driver side was dripping gas..... so I will be replacing the injectors tomorrow, and I will update on how the truck is running.

I replaced the injectors, and gaskets, and now both injectors seem to be dripping... i really don't get it. It says to put trans fluid on the injector o rings. Should I take it all apart and soak these o rings in trans fluid? or was it find i put a couple of drops on? or could something else be the reason the injectors are dripping?

Okay figured out the problem. It was the EGR valve... who would've thought...