P0641 Loss of 5V Reference/ Fuel Trim 3 30%
Hi there.. I have been struggling with the code above on my 2010 Cobalt (about 70K miles). Initially, I replaced the MAF sensor, cleared the codes, and it ran fine for 350 miles or so, and then threw the same code. All the listed diagnostic tests come back OK, or N/A (assuming this means they are not relevant). It seems to come and go, so I am now thinking it is a loose wire, or bad connection somewhere. Anyone know of a "likely" place to start? I also noticed the Fuel Trim 1 is ok, but the STFT 3 & LTFT3 were running at 30% at the time of the code trigger. Any ideas or thoughts are welcome on that as well. Thanks!!