I have a 98 zr2 blazer that I started up last week and it had a super sloppy idle. It used to pur like a kitten. I cleaned the throttle body and replaced the mass airflow sensor and it still didn't help at all. What it does is idles supr r low at like 400rpm then itll start to die and catch back up with its self and shake really bad. I was mess in with it yesterday and found out that if I unplug the ac pump then it idles perfect, but if I plug it back in, then it goes right back to being sloppy again even if my ac is off. Could it be tge solenoid that tells it to idle up when the ac kicks on? If it is tgen couk someone please tell me the name of that solenoid. Also it needs an alternator but it needed one before this happened. I need help bad. Its my daily driver to school and work and i just want it fixed. Thanks