constantly codes pertaining to running lean, etc
I have replaced the evap canister, gas cap, purge valve, upper O2 sensor, Mass air flow sensor.( It has not coded for the lower O2 sensor, therefore not replaced (but could be next!) All this since September 2019.
It will run awhile with the code off after repair, but then the code appears again. Sometimes the code goes off by itself, but comes back on again. The MAF sensor was the most recent repair (2 days ago) and that seemed to do the trick. Ran for 225 miles with no code so I went to emissions testing station (tags due Jan 31). because of long line of cars, I shut car off to wait. When I turned on car the code was back! Help! This has frustrated me and two of the best mechanics in Nashville!
Vacuum leaks and exhaust leaks can cause a lean code.