hi guys,

i have a 1988 camaro iroc

brand new rebuilt 350 tpi engine stock

no cat or AIR

still has egr, the rest is all stock.

had low fuel press. before so i replaced fuel pump and filter.

now its 50psi key on and 46 psi running idle, perfect fuel pressure.

car ran great the same day i put it in and the day after.

the next day, in the morning it started acting weird the engine missing (mot missing but cuts out) and rough idle.

from then on for about 2 weeks it ran fine when cold and started perfect, but when engine warms up it acts weird again w/ hard starts and has been getting worst day by day. but runs fine when cold.

has new gm/ac delco- plugs, plug wires, cap and rotor, ignition module, pick up coil tested fine, ignition coil tested fine by ohm testings? fuel pressure still good. no trouble codes.

injectors ohm test is good all within 16 ohms +/- .2 each

it idles fine, sometimes after wartm start up the idle will bounce up and down from 750-1250 rpms and then quit after i press the gas.

what could be the problem

i'm thinking:

ignition coil or o2 sensor

 

Check all your vacuum lines, sounds like a vacuum leak.

 

hmmm , mostly your ignition is new, except for the coil so check that out. check the knock sensor, and the ESC module as well.. when i had a bad ESC module the car idled very rougly and kept cutting out , but the ECM gave me the trouble code.

 

it runs great when cold?

 

I'd say check/AND replace the IAC. I had a similar problem where when I started the car, it would die when I hit the gas. It was my TPS sensor. Replaced it and it ran fine.

 

Do the TPS/IAC test/adjustment (from thirdgen.org tech articles) but I'd be looking at the o2 sensor. I think it's the only sensor that's active during closed loop but not during open. Hell it's cheap, $25. Do it anyways.

 

I had the same problem. The car want to die at idle or coming to a stop, then the rpm would bounce up and down. Also, ran ok under load but would miss with no load. Found a shorted injector. Disconnected the injector and the engine rpm was steady, with of course a steady miss. Thought I would replace just the one. It ran fine until it started warming up. Then it started over just like you said. Turned out in burned out the injector driver in the computer. Replaced the computer, which was the source of the problem, and all the remaining injectors (along with changing prior to finding the computer problem: plugs, wires, cap, rotor, dist module, pick up coil). Runs great now.