4th gen LX, when idling in drive my RPMs are 500, sometimes even 400, and is very rough. this is entirely too low. should be about 700-800 right? Also when ever I change from like drive to reverse or vis versa, the RPM's dive below 300, to near stall out levels. Couple times i've had to hit the gas to keep from doin this. I'm gonna check out my intake tomorrow, perhaps IAC valve issues. Anything else I should check?