Idling characteristics with bad MAF sensor?
 

Does anyone know how an otherwise good running BRZ idles when the MAF sensor is bad or just disconnected? I think a piece of debris may have gotten sucked into my intake (embarrassing story) and ruined my MAF sensor. At idle my engine oscillates between 600 and 2200 rpm (about a 1 second frequency). It's not running good at all.

Thanks, Mike

From experience the car should idle fine with the MAF disconnected, maybe a little rougher but it wouldn't be fluctuating like that. Typically people know a MAF is bad when the car runs better with it disconnected, signifying the MAF is giving a bad reading. I wouldn't drive without the MAF but you can start it up disconnected to get an idea. Was it large debris that would have impacted the sensor or just made it dirty?

I disconnected the MAF, and the idle was still bad, so I figured the MAF was OK, per your advice. So, I moved up the air intake to the throttle body. I removed the flexible intake tube at the throttle body and after opening the throttle by hand found a 1/2" sliver of loose plastic. I removed it, and now the car runs perfectly again. I suppose the debris was somehow interfering with the throttle or throttle position sensor.

That is scary. What was the plastic from? Could more of it have gone through your motor?

Time to fess up. What did you do?

eeek, this sounds scary..

hope nothing made its way inside..