So my car will idle but it weird. Goes from 1000rpm then drops to 500rpm and it sounds like the car is stalling(actully did a few times). The check engine light is on but idk. It just inspected today which is weird. I did put a CAI in with out useing the Mass Air Flow Sensor but after I noticed that the check engine light came on I put the oringal back on. Now it just keeps messing up. Did I screw some thing up bad?