I have a 98 mustang convertible. I just replaced the computer and the fuel pump. The car is still running rich. Checked the fuel pressure, 70 at the pump, 41 at the rail.
When I start it, the smoke is really thick and will foul the plugs in a few minutes.
Any ideas? I am desperate.
If you have a CAI "cold air intake" it will be much easier. But if you don't then you need to pull apart your breather and look at the mass air meter. There should be 4 wires if there is more don't panic just look closely at the sensor and there should be letters like SIG, GND, REF, BATT, or something like that. If it does have only 4 wires then the wires you need to test are the middle two (SIG and GND) you will need a digital volt meter set at 20 volts DC or so.
With the car running at idle probe the two wires and see the voltage reading. It should be anywhere between 0.2--1.5 volts at idle. Then rev the motor to see if the voltage rises slightly "at 60MPH it should read 2.0 volts but this is at load conditions" Also you can disconnect the MAF harness connector and use an ohmmeter and probe the terminals SIG and GND. If the element inside the sensor has been damaged it will be indicated by an open circuit (infinite resistance)