Idling always off
 

To Lovers of Altima, I have 1994 Altima, SR20 engine.

My problem is that after the mechanics have adjusted both air mixture (air filter sensor) and AAC valve (near the manifold), after a few weeks, idling is not consistent plus engine sometimes goes dead after leaving your foot from the gas pedal....

Last mechanic suggested that it could be the AAC valve is almost busted or needs to be clean by using a brake cleaner. They cleaned it but then idling is still crazy after three weeks.

Any suggestions???