I have a 2005 Pontiac Aztek. My brother in law recently replaced the thermostat and for whatever reason, messed around with the sensors. Now, when you start the car, you have to hold the gas pedal down a little bit, else it dies. When it does run, it backfires through the intake, runs rough, and revs up to around 3000 rpm on its own.
We’ve tried checking the fuses, resetting the computer and cleared all the codes, yet nothing seems to be working.
Any ideas on what to do?