A couple of months ago a got P0174. This happens when the weather turns cold and goes away after a couple of resets. Lately I've been getting P0172. If I clear it it comes back consistently during the second drive cycle. If I don't drive the car for a few days the CEL goes out but comes back. I've checked for vacuum leaks and cleaned the MAF sensor.

Does this too lean to too rich pattern and the CEL reset suggest a particular failure to anyone?

 

One side rich, other lean. Watch fuel trims for clues or take to a jag indy.

You may still save the cat(s).

 

Thanks. I apologize for not being clear. First I got the lean bank code which went away after 3 resets. I checked for vacuum leaks but found nothing. Then about a month later I got the too rich code which I had never gotten before. This code actually clears itself if the car sits for a few days, or at least the CEL goes out, but returns in 2 drive start cycles. My scanner only shows trims when the code is set so I can't actually see real time data. I guess I should invest in a new scanner.

What I was wondering was if the pattern of too lean and then too rich plus the CEL reset after sitting might point to a particular condition or component. e.g a faulty MAF sensor, EGR, etc.

Thanks again