My 2009 Cobalt is bucking and playing games on acceleration, but only when the a/c or windshield defroster is on. Otherwise, it purs like a kitten. Before turning my A/C on back when the weather was cooler, I had no SES light, but now it is on. No strange sounds or anything like that. I have already cleaned the throttle body. Thoughts?

 

What codes?

 

SS or non SS.

If it's a non SS car I would check all of your vacuum hoses. Check your intake for air leak.

 

Thanks guys. Non-SS and codes are for incoming air temp and maf sensors. All connections seem fine and it is strange it is only when AC is on. 5 speed also.

 

I thought this was normal my car is a pita when the ac is on. I always attributed it to the extra drag of the ac compressor causing the rpms to fall unnaturally fast but ive never had a code

 

Try cleaning the maf. I'd guess your ecu is seeing different things when the load of the AC kicks on and it bouncing between tables

 

Thanks guys. What is safe to use when cleaning these things? Is the iat part of the maf?
Thanks!

 

Just read the instructions. Should be able to buy just about anywhere. Works really well from what I have seen.

 

are you putting the ac on high?

I would clean the sensors and verify all vacuums are still connected correctly

 

No luck with the cleaner. All connections look good. Looks like it is a new maf sensor for me. Given both the IAT and the MAF are the same unit, and they are both throwing codes, I would think that is a pretty good indication I need a new one? It definitely has a misfire or something...I can here it in the exhaust from the back.

 

New MAF seems to have fixed the problem. SES light went off after the first start. $60 and about 5 minutes to replace.

 

Glad you got it fixed.

Definitely on newer MAF cars where the IAT is integrated and you see IAT/MAF codes all setting with drivability issues, there's something going on with the sensor.

The one you removed, you said it looked recently replaced, was it an aftermarket one? The non-OEM ones just don't work as well or last as long. They are cheaper but you pay the price on longevity.

 

Rule of thumb is to always go OEM unless there's an aftermarket part that's proven to be better (like Powell CAB's).