I have a 2000 alero with the 2.4L vin "T" engine, and recently it began surging at idle and now at red lights. it will idle around 750 rpm then suddenly drop to 400 and surge violently as if trying to keep itself from stalling. I cleaned the iac valve and the tb. I also replaced the iat sensor and when the problem persisted I was then 100% sure the MAF was dirty or faulty. well did i feel stupid when I learned the 2.4 vin T has NO maf? so my question is without a maf sensor there has to be an equal sensor with the same general purpose. there is only so many things before the TB that can cause this type of surge. there is NO vaccume leak.( this much i'm sure of) can anyone help me with this problem?

 

is it tripping an engine light? if not id say clean your intake and throttle body with some intake cleaner. could be a lot of things.