The NOX reads high at 15 MPH but passes at 25 MPH. No check engine light. I replaced the spark plugs and air filter before I took to Smog test.
I was told to clean the Mass Air Flow Sensor. I have never cleaned before.
Does this sound correct or are there other problems to look for?
Last year the check engine light came on but went out after two days.
have the same problem?
Monday, August 23rd, 2010 AT 9:22 AM