Ford Repair: Check Engine Light, mass air flow sensor, mass air flow

Question
My check engine light came on, went to get it diagnosed, they say it was the mass air flow sensor circuit, I changed it, the light was still on, I got a full tune up, light was on, I got an oil change, light still on, each time I got something donr I disconnected the neg. from battery, to try to reset the check engine light, I have a 94 explore 4.0L , What else can it be........ can u give me some sort of an Idea thanks....

Answer
The Check Engine Light comes on when there is a problem in the Emissions System.  The system will have to be scanned again for Diagnostic Trouble Codes (DTC's).  The code will indicate where the computer sees the problem.  The code doesn't mean that the sensor is bad, it could be a wiring problem, or a symptom of a different problem.  Changing the oil, or a tune-up wont effect the emissions system.  A common repair for a Check Engine Light on this vehicle is a DPFE Sensor (a.k.a. EGR Pressure Sensor).  But I would have the system scanned before repacing any more parts.

I hope this helps,
Dave