[davezolp]

Hi All-

I hope someone can give me some direction. I have a 2012 w/ 1.4 L engine and 170 K miles. Engine seems to start and run fine and gas mileage is good when cold. When engine reaches operating temp, things go bad. Rough idle, feels like it is missing, mpg is about 20. I've installed the pcv bypass, replaced valve cover, replaced MAF sensor due to lean codes.

Nothing seems to help. I can't remember where I read it, but I thought I saw that a bad spark plug or coil may cause misfires when it gets warm. Could this be it?

I'm at a loss.

 

[davezolp]

I had all the lean codes indicating a leak and decided to do all the replacements (valve cover, cruze kit). Latest code was P0500 indicating down stream O2 sensor that I replaced. (Probably due to the misfire)

 

[davezolp]

I had all the lean codes indicating a leak and decided to do all the replacements (valve cover, cruze kit). Latest code was P0500 indicating down stream O2 sensor that I replaced. (Probably due to the misfire)

oops that code is wrong. Can't remember which number it was but it indicated downstream O2 sensor