I am questioning if my 02 simms are working correctly as my car has been crapping out on me. Is there a way to test an 02 Simm to see if it is functioning properly?
Thanks

 

A failed O2 simm shouldn't make the car run any differently. It should set off an SES light, that's about it.

Dave

 

The front O2's are not replaced with Sims since they are used by the PCM to monitor and control fuel trim. The back O2's are only to monitor the efficiency of the cats. This is where the Sims are used. If your engine is crapping out after running, it's because of something else. If the front O2's where the problem, you would notice the problem as soon as the engine goes into closed loop mode. If that is not the case, the first thing to check is the fuel pressure during the time of the problem. Get a fuel pressure gage with a hose and tape it to the windshield and take it for a drive. See what happens. If that's ok the next thing to check is spark. That can be done with the engine cold and a blow dryer to heat things up one at a time.