car idle bounces, then when at stop sign it either stalls or it sputters. on 1993 Chevrolet Lumina

so when im driving the car it drives good but when i get to a stop light or stop sign the car sputters and the car sounds like it wants to shut off. the rpms bounce at 500 and some time drops to 400 when at a stop.
and when the the rpm gauge drops the dash lights dim a little.
i replaced the IAC sensor, cleaned the throttle body, did a idle reset, put some injector cleaner in, and problem is still there. if anyone has any ideas PLEASE HELP

Asked by for the 1993 Chevrolet Lumina
Check the vacuum connection port at the rear of the intake for a cracked or loose hose.
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1 more answer , 4 more comments
Which engine
chevy lumina 3.1 v6
Do you have a Tech1? Just trying to help, if you reset the idle you must have a Tech1.
what is a tech1?
It's then scan tool used to relearn idle on a 3.1 v6. Not sure how you reset the idle without it. When you change the IAC-Idle Air Control motor it has to be relearned with a Tech1. I'm sure you have more problems, need to run data for short term fuel -