I really need some advice.
I have a 2005 chevy tracker. It came from the factory with a 2.0 suzuki engine. It has failed emission 3 times for NOx.
6 months ago, had the top of motor rebuilt. Coolant is good, fan is running, car does not over heat.
1 time fail, changed the Cat Converter. I don’t remember the data for NOx
2 time fail, changed the EGR Valve. NOx 1000+
(when I picked the car up the check engine light was on for the 1st time, then the mechanic cleared the code that caused the light. He said it was because of the change of the EGR valve.)
3 time fail, don’t know what else to do. NOx 800+
Any advice you can give will be appreciated.