Hi all. New here but lurked many times. Appreciate the efforts of all contributors! Our ride is a 1991 Z28, 5.7 TPI. Factory performance rear axle (rear disc brakes). completely stock. It's been a pleasure to have and drive. I wrench on everything I own and am electronically connected so to speak. My very similar problem to what I see on the forums here is a rough unstable Idle as soon a CLOSED LOOP is achieved. Start cold and she runs (Idles) pretty well until closed loop and then the jet engine sound (IAC OPENING UP) gets really loud. Even without the monitoring hardware, I can tell its going rich and the ECM is commanding the IAC to open wide open to try and get the mixture back on track.
Things already done:
1227730 ECM swapped (I have 4 )
Plugs
Wires
Cap
Rotor
Spark is strong (Yes I got bit....)
O2 sensor
Ignition timing is stable for a 150000 mile car. It's not jumped a tooth anyway
MAP and TPS functionally verified( unplug one or the other and engine still controls timing. SERVICE ENGINE SOON LIGHT comes on. Unplug both and engine almost DIES if butterflies are opened a little.
EGR (which was bad by the way. Applied vacuume caused no movement and you could breath through the port on the valve )
Injector inspection including removal, pressurized front and back flushing, leak down testing and spray pattern verified.
Fuel pressure tested (Guage will be on the car until it runs right...)
Fuel filter
Fuel pump
Intake manifold re-torque ( All but one were super tight. One was just tight (got about 1/8 turn).

I have been reading that this may be caused by a bad MEMCAL unit, which I only have ONE of (The original) The other ecm's I have were from other vehicles and not Camaros.
Heres the questions
1. Am I right in thinking maybe the MEMCAL and how often does this happen
1. Any other checks I can make that I might have missed?
2. Best suggested place to get another stock MEMCAL?
3. Suggesttion on where to send these MEMCAL units I have to get them reprogrammed as a 1991 Camaro.

Okay so I wrote it all down in one spot here so I can remember it and am going to fish around on the site for good info but anyone willing to comment/help out would be greatly appreciated. Thanks in advance to all you Camaro fans!

Oh yeah and valve guide seals cured the mosquito-fog-on-start effect really well!

Links or comments appreciated!

Measured the resistance of the injectors. The manual states "10 OHMS or more". I have 4 that measure 16.5, 1 that measures 12, One that measures 7.5 and 2 that measure 5.1 !!!! The LOW OHMERS will load the injector drive signal down for the entire BANK and will foul up the mixture control. I am injector shopping now.

Theking says:
"If the injectors are bad, I would go with the Bosch III modified from Jon at FIC, They have exellent spray pattern and they are flowmatched (each set) and he leaves 3 years warranty on them, costs 169,95...

http://fuelinjectorconnection.com/sh...&productId=134

Get your injectors checked, bad injectors can cause alot of things. Call Jon up and he will help you out "

Any other suggested injector suppliers out there that have been good to anybody??

Just ordered the injectors from Jon at fuelinjectorconnection.com. He said mine are supposed to be 22LB injectors. This is what he is sending. My injectors look black on top and green on bottom. Some time ago I read where the injector could be identified from its color. Mine appears to be like the DELPHI units that are on their website but the units I am getting are the BOSCH Gen III. Can't wait to see what goes on next but it will be next week.
Thanks again Theking.

Fuel injectors fixed it. Fuel Injector Connection as in the previous post, provided the injectors. Gen III Bosch rebuilt units 170 bucks for all 8.
Good to deal with and the products work. So far so good after resetting the IAC and driving it a while to let it learn again.

Thanks again Theking!