I have a 2013 Malibu LS with 126000 miles on it. I had a bank 1 sensor problem so we change both O2 sensors in it. That fix the check engine light problem but then it started stalling when you go to start it from cold. It goes through its normal high idle when cold then when it settles down it sputters and stalls out. I put new plugs new throttle body new cam sensors and new intake gasket. It shows no codes but still stalls. No vacuum leaks found. I've had this at my local mechanic with no luck so I took it to a GM dealership and still no luck. I'm over $1,000 in parts and labor and my car still doesn't run right. It has always ran fine right before the 02 problems. Any helpful advice would be greatly appreciated.
Thanks Mike
Then it's directly tied to the o2 sensors you replaced. Did you go back with gm sensors?
Yes. All parts replaced were GM parts. Had aftermarket at first but still has a bank 1 issue. Installed gm sensors and bank 1 problem was gone. But then the other issue started
Double check the new o2 are good also make sure they are the proper ones. New doesn't mean anything. Check the wiring and harness, make sure you installed properly. Get a scanner and look at live data for o2 . If you don't know how to read live data/graph a simple google search will show you how. It sounds like the issue happens when car goes into closed loop. Since it's happening after o2 install it's probably a o2 issues. Double check that you didn't disconnect something in accident. If I remember correctly there is a fuse under the hood for o2 sensor, it's listed as emissions. Check that also.
I asked my mechanic that very question if we got a bad sensor. His scanner showed it was running normal. I dont recall the numbers he gave. Even the GM dealership said all was running fine. I will double check to see if any wires were unhooked and the fuses as well.
When it stalls, are you able to start the car with starter fluid? Or have you tried pressing the gas pedal all way down while the engine is cranking?
I would also clean the MAF sensor.
After it stalls it will start right back up. Put a new maf sensor in as well. Scanner shows its working properly
Change the fuel filter and pressure test the fuel pump. Odds are that the fuel pump is on its last legs.