1988 Delta 88 rough idle

1987 88 started bucking, cutting off, wouldn't start for a few days... replaced battery, alternator, plug wires, starter,idle air control valve. Took ignition control module to autozone for test.. passed. got a icm for junkyard, but failed test. got a brand new icm for autozone. the original icms had same symptoms but the icm from the junkyard makes my car run but failed autozone test. with junkyard icm has ruff idle. need help plz

Hmm, rough idle means? Misfire, does it acclerate ok or just miss/act rough at idle. ? Many things can cause what you descibe, bad plug, crossed wires, bad coil, bad injector, stuck egr, low compression in one or more cylinders.

once the car starts up and achieves operating temperature idle speed drops and almost stalls then tries to correct itself but slows back down. it does not do this with the mass airflow diconnected

Make sure you have sufficient fuel pressure, then replace the maf, or check the connector, they were noted for the connection/pins making poor contact. No codes? done a scan?

fuel pressure is fine, no codes

can you explain the new and original icm not working but junkyard one works

Not without checking components on site,there were 2 different icms in those years also. BTW AZ's test procedure for the icm's has proven to be about 50% accurate.