tbi stumbling
 

i have a 1988 gmc 1500 pick up it had a 350 tbi i recently replaced the engine with a 1995 tbi 305 now the truck stumbles and pops under load i recently replaced the tps,iac,egr switch,spark plugs ,wires ,cap, rotor ,dist control moduel,i dont know what it can be can someone please tell me what it can be

What your timing degree at? Was this 305 rebult or just shoved in? How many miles are on it? You are smart enough to change the E-Prom correct?

its set at the factory spec 0 degre the 305 has 100,000 the 95 chevy was a 305 5 speed the 88 gmc is auto the prom wouldnt work do you know where i can get a 305 prom from, can one out of a camaro or firebird work

Check the Timing and Fuel pressure....Had a 93 TBI which had a bump pump, thing would start and run but if you didn't feather the throttle it would stumble

thanks im going to check the fuel pressure and change the fuel filter allso im allso going to change the coil and egr valve and 02

Your ECM thinks there's still a 350 in there, so all the fuel delivery calculation it's doing are dead wrong.

Time for a new MEMCAL or a custom chip.

i have a 305 ecm out of a 88 camaro tbi in the truck right now its still doing the same

The knock sensor and ESC module are also different between 305 and 350. You should check out thirdgen they have all of this info up there. You'll just have to reverse most of the info I guess since most people go from 305 to 350 and not the other way round.

composite intake 305? does it have a extended start or rough idle upon starting than cleans up? if so my money is on the fuel pressure regulator located under the intake.
put a fuel pressure tester on it, cycle key on for the pump to engage. turn key off. if pressure drops 5-10 psi in the first minute or so you have a bad fpr. costs about $200 for the fpr & gaskets if doing it yourself.