I have a 350 TPI abd I have a problem wit my idle, sometimes its fine around 1000 in park and about 600 or so in drive, but then other times its all over the place and want come down sometimes. I can hear the idle air control valve poppin like its tryin to find a spot but it cant even after i cut the car off sometimes. could it be bad and the egr valvue i have my air stuff disconnected and taken off. is that valve still bein used though and if so how do i kno if its bad and could be causin my problem