quick info....1996 chevy tahoe, 4x4 5.7L
boggs down in park or driving like no fuel. replaced fuel pump and filter cleaned all lines, no change. when it boggs down and back fires ( with fuel pressure guage saying 52 to 57 lbs) I can turn it off and restart and it runs fine for a few miles then does it again. replace computer, ignition module. cap rotor wires plugs coil ( needed these anyway). still same problem. 3 shops later still same problem. all cylinders good compression, never run hot, high oil pressure. oh and no computer codes with either computer old or new. anyhelp would be appreciated I have to pick up 2 horses in need of rescue for sheriff dept and can not get to them....Thank you

Welcome to AF, proper fp is 60-65 for a Vortec.

[I talked to chevy man at local dealer, he said with guage I am using allow 5+ to what my guage says.

when you said you changed the fuel pump and filter did you also change the inline filter or both? Just a thought.

I replaced everything and cleaned all line to intake

[I talked to chevy man at local dealer, he said with guage I am using allow 5+ to what my guage says.

Even adding 5 to 52, you're at a low pressure of 57 PSI. CPI injectors are very sensitive to low pressure. And if you're using an inaccurate guage, how do you know to only add 5?

Did you also check the fuel pressure regulator? The pressure should increase with the vacuum hose removed from it. Drive the vehicle and see if the fuel pressure drops when it boggs down.

You have enough fuel, what yur missing is air. Your cat converter is bad and not letting enough air into the cylinder. Also causes backfire.

[Already tried that both cats removed and replaced with inproved flow and still happens. I will remove vaccume hose from regulator and try that but when it boggs down no change in fuel pressure. New fuel guage says 63 lbs.

OK, it seems the fuel pressure issue is done. Here are some more things to check.

1. EGR valve.
2. MAP.
3. TPS.
4. Fuel Injector Balance test.

The EGR is listed in both "lack of power" and "backfire" symptoms.