'98 Tahoe 5.7 Vortec runs like crap, backfires in exhaust and intake - need help, pls

[Tempritscher]

My mechanic says the dizzy gear is not worn.
He thinks the engine gets too much gas.

Maybe wrong signals from the PCM? (Already installed MPFIm checked MAF, MAP, ECT)
Maybe wrong fuel pressure?

I am wondering about that the problem increased creeping, as written in the beginning of this thread.
Could a malfunctioning electronic part such as the PCM fail creeping...?

 

[SAATR]

I'm sorry that I did not come across this thread earlier. I sincerely hope that the problem has been corrected by now, but if it hasn't, I would suggest verifying your fuel pressure. The Vortec injection system must have around 4 to 4.2 bar fuel pressure with the key on and engine off, and at least 3.8 bar at idle. A failing fuel pump or regulator will cause precisely the symptoms you describe, and since you have already replaced the CSFI unit, that leaves only the pump.

Again, this is another direction to look in if you haven't solved the issue yet.

Ego mobili

 

[GMstrong]

any updates?Pull the dizzy out and look at it will only take 10mins if that then check it off the list.If the teeth are thin its bad.Also have you ruled out the dizzy cap?They are prone to moisture.