Hey everyone. I have an extremely strange issue with my car and I've tuned to this forum because I'm at a complete loss as to what's going on so I really hope someone can help. A quick background of the car, it's an 06 Cobalt SS that I turbo swapped. I ran the car all last summer turbo swapped without issue. A couple weeks before I put it away the car started acting very strange. As I cruise down the highway the car will randomly start running pig rich and the check engine light then flashes constantly with misfire. Logging the car, it's fine till it gets to operating temp then starts to do this. It shows open loop fault and starts commanding 10.1 AFR. Things i've tried are:
- Changed MAF sensor
- Changed MAP sensor
- Changed 02 sensor (rear is deleted)
- Changed ECU
- Tried a few older tunes thinkning a file may have gone corrupt while making changes
- Reinstalled my rear 02 sensor and put all DTC's back to stock. ZZperformance who deals with Cobalts said the car will do this when it can't complete a Catalyst Test. HPT shows the test being completed.
I've found 2 others with the same problem with a basiclly stock SS/SC Cobalt in the same boat as me so I don't believe it has anything to do with my turbo swap. But i'm completely stumped. I don't know why the car is showing an open loop fault and then commanding pig rich. Hopefully someone here can help or has had the same issue. I will attach a log to see. At the 5 min mark is when the car starts acting strange.
Thanks