Anyone know how to check a crank sensor?
 

Before I go out and buy a new one, if I hook up my ohm meter to any of the prongs on the crank sensor harness should I be getting a reading? I'm not getting one which makes me think there's a problem.

Nevermind.
 

Yes, there is a reading on two of the prongs. I found this out by buying a new one and checking it. Old one was bad so now my car starts fine. It's still idling bad and shows code 1222, Lambda control. I'm trying to figure out exactly what that is because it idles like crap. Any ideas? I've already checked for vacuum leaks and cannot find any. Also, when i try to rev it it hesitates. It has a new mass air flow sensor. Could it be TPS? 1991 325ix. Thanks.