TPI rough idle problem please HELP!

[91chevyz28]

91 Z28 w/ 305 TPI has rough idle and at idle if throttle is cracked it bogs then idle goes up.Sometimes it pops out of the TB. I've changed the following:
spark plug wires,egr,new distributor w/ cap,rotor and module,map sensor.TPS senser,oxygen sensor,have fuel pressure guage(pressure holds when ignition turns on does not drop),timing is set,and new coil(MSD) any ideas I am stumped!!!

[camaroAL]

sounds like ur dist. is one tooth off

[91chevyz28]

it was doing it before i replaced the distributor. thanks for the reply.

[Teds89IROC]

could be the IAC..(Idle Air Control valve) You could try cleaning it first with carb cleaner before buying a new one.

edit: When you raise the rpm's do they stay up or come back down?

[camaroAL]

how many miles are on this engine? also if its popping out the tpi i wouldnt rule out a bad lifter or timing chain and gear issue

[91chevyz28]

i forgot to mention i cleaned the IAC and changed the fuel filter, the rpms stay up. they do not drop down. the car has just over 82000, i was thinking i might have a bad injector, but i don't know how to test the injectors.

[camaroAL]

when my computer went bad i had this prob. also

[91chevyz28]

how did you determine it was the computor? did you do a test w/ a volt meter on the computer?

[camaroAL]

i had checked everything else possible, dist, cap, rotor,plugs,wires,timing, iac,sensors.etc... and luckily i knew someone with the same car, i tried the computer and bingo.. so i threw out my tpi and went to a carb.

[Teds89IROC]

I had this problem with the t-bird months ago except for the popping. I cleaned the IAC and it did nothing. I replaced the IAC and that was it. Are you throwing any codes?

[BonzoHansen]

checked for vacuum leaks?

[91chevyz28]

i have no codes and i also checked for vaccum leaks. i also sprayed carb cleaner around the intake.

[The Fixer]

Jay, make sure the plug wires are in the right order, and check the battery voltage with the car running. If the ECM isn't receiving the proper voltage, it may do wacky things.

Also, I know you said you changed your ignition module, but it's possible the new one is bad, or the pickup coil in the distributor could be bad. Let us know what you find!

[91chevywt]

Theres plenty of hoses throughout the engine compartment that could be leaking vacuum. It may help if you unplug some of the manifold connections and plug the manifold with a cap and see if theres any differences, or look at any questionable hoses.

[91chevyz28]

hey steve, i installed a complete brand new billet distributor. it came w/ everything and i checked the plug wires. it does the same thing before i installed new wires and distributor.i also have a new battery.
thanks for the ideas.