My Check Engine Light has been illuminated, I've brought it in for service and the error codes are: PO172, PO174, PO171, PO175 which say the fuel/air ratio is too lean and too rich. Any ideas what would cause this? Everything else has been working fine except I have noticed the rough idle other users have noted. Any help would be appreciated. Thanks.

 

The way I read your codes would mean that the left side is lean the right side is rich.

I would reset the PCM go for the second reading and if the same would replace the left side O2 sensors.

tom

 

Dead or very weak O2 sensors will cause conflicting codes.

Replace the O2 sensor(s), reset the codes, and see waht happens.. Your problem will likely be fixed.

Steve