I have a 2001 mustang bullitt that is showing service engine light on. Took it to mechanic and he put 2 different machines on it to show code for problem. No codes coming up and he can't turn off the light. I need car smogged soon!! Wont pass unless light gets turned off. I have been driving the car for months there is nothing wrong with it. Car has 96k on it and no service except oil changes and cleaning air filter.

SOURCE: 2004 Ford explorer will not start

Sounds like connections or cables. They may appear to look good but if they are aftermarket terminal ends they get corrosion under the bolt down clamp that holds the wires in. If they are factory cables that are molded on to the ends of the wires the same thing can happen. The easiest and cheapest thing to try is to put aftermarket terminal ends on the cables. Make sure you wirebrush the ends of the cables after you strip them and tighten them evenly and securely. Also clean the battery side thoroughly. If this doesn't work check the starter relay. Its the first place the red cable bolts to after the battery. Check the connections and try putting a jumper wire between the battery positive cable and the small terminal marked with an "S". One of these solutions should take care of this.

SOURCE: 06' Ford Explorer engine light wont go off after repair

Yes, that sounds correct to be calibrated.and probably is what is causing your problem. Mass air flow sensors hardly ever go bad. They get dirty and set a code. Garages will try to sell you one when you can clean it with a throttle body cleaner. If you have your old one, clean it and put it back on, try it to see if it works better.

SOURCE: 2001 ford mustang service engine light on

IT ALMOST SOUNDS LIKE YOU MAY HAVE A VACUUM LEAK SOMEWHERE. USE A LENGTH OF RUBBER HOSE AND HOLD IT UP TO YOUR EAR TO PIN-POINT THE LOCATION OF A VACUUM LEAK. HOPE THIS HELPS. LET ME KNOW PLEASE. THANK YOU IN ADVANCE FOR AN HONEST RATING AND THANKS FOR USING FIX-YA. P.S. EGR VALVE IS VACUUM ACTUATED

SOURCE: code p0302

Look at the wire and plug to cylinder 2, for cracks or damage, if nothing is found run a compression test need 100psi min, and then check the injector, you need to meshure resistance with a multimeter, and compare to other injectors something like 12 to 15 ohms would be good i think.

SOURCE: Ford Taurus 1999 "Service Engine Soon" Light ON

just don't bother and next time go to auto zone that check it for free
PLEASE RATE ME TO 4 THUNBS