Z28GEN3

A friend has a 4.5 L TBI V8 engine and is having some problems with it, the first problem: when you put it into drive-at about 20-30 mph it acts like it has no power and this is with the pedal all the way to the floor, then after it struggles to reach 30 mph it acts normal. 2nd problem: when its motion around say 50 mph and you let off the gas pedal and then stomp on it-it bogs and acts as if it wants to die. I've checked fuel pressure and it reads 10 psi, the TBI has brand new injectors, the reg diaphram looks okay, the gaskets look good, but their trying to get it to pass carbon-dioxide test the limit it 15.0 and rite now its showing 15.6.

I mentioned a bottle of rubbing alchol next time before they take it into have it tested. I cant think of anything else rite now except to put it on WinALDL and see if its soemthing else. also the cone spray from the injectors is not consistent, in that it fluctuates from dripping to a light spray.
Does anyone know what could cause this?

ShiftyCapone

iTrader: (7)

10 PSI is a tad on the low side. What does the pressure drop to when you hit the gas a little?

Z28GEN3

okay we put it under load and the pressure dropped maybe 1 psi and thats when it bogged and it sounded like it backfired a few times, i couldnt get anymore then 10psi on the gauge even when the throttle was half open.

from what i've been told the ignition system has been rebuilt/replaced, ie plugs,wires, distributor cap & rotor, pickup coil and module.

Z28GEN3

Also i couldnt find any info on the 4.5L V8 TBI i looked for winaldl versions that would work and wasnt successful.

scubas_90rs

what is a 4.5 in i know that this doesn't have anything to with you question but i would like to know

Z28GEN3

to answer your question its an x-body(caddy) i know i'd never heard of it before, nothing like my camaro.