2009 G37 Coupe S....My "service engine soon" light comes on when the gas take gets to 3/4 full and then goes off when it gets to 1/4 full. Of course, every time I have taken it in it's after the light goes off. This last time they changed out the gas cap which obviously didn't work since the light came back on.

Any thoughts or suggestions?

 

If it comes on at that level of fuel consistently, why are you not taking it in to them when light is actually on? Don't fill the car over 3./4. If it is below 1/4 when you have the time to take it in, just fill it to half way to make the light come on before taking it. Many auto parts stores will check codes for free, stop by one while the light is on and have it checked to see what the code is.

 

try replacing the gas cap too

 

 

I would make the appt to take in and right before I would head that way the light would go off. But that's a great thought about stopping at the auto parts store. Alot more convenient than driving to the dealership. Thanks for the tip.