The first time I brought my car in for smog check it fail functional test because CEL was on for O2 sensors (I did not know this because the check engine light bulb was burned out), I replaced the oxygen sensors, CEL light bulb and cleaned the MAF with MAF cleaner bought from auto parts store. The car ran great and accelerate very well, 500 miles later I took it in for a retest and it Fail the Emissions Test (which passed before the o2 sensors replacement). I checked all the hoses and I didn't missed anything. I only take a part the MAF sensor and the intake hose to get access to the o2 sensors, replaced it after o2 sensors repair. Not sure how to diagnose this one since it was passed before and no CEL at the moment. Any suggestion would be appreciated.
have the same problem?
Friday, October 4th, 2013 AT 4:32 PM