Re: '03 Crown Vic has my mechanic stumped
We unhooked the belt and it still squeels internally. The noise has almost gone away with some lucas oil stabilizer. My only concern now is the misfire. The odd thing is today we went for a drive with the diagnostic computer running, the car ran well for 4 miles, then started missing badly, the computer set 7 codes, they were "Cylinder X Circuit Malfunction" for every cylinder except #3. My mechanic has tested the wiring harness from the pcm to the COPs and was fine. The ignition coils and plugs are fine, the fuel injectors are fine, the engine grounds are fine. Another interesting point, at a stop light the computer was leaning out the fuel mixture to -0.0% and when we tried to leave the stop light, the car would not move at all and then as if a light switch had been flipped it ran flawlessly. The only other code which we have never gotten before was "Cylinder Head Temperature too low 53 degrees" which was after the engine was fully warmed up. Mechanic tested spark on all cylinders and it appeared to be random, we replaced the PCM with one from an 03 Grand Marquis and the spark was then constant, but the fuel pump would not run off of that computer. We are leaning towards the PCM being shot, although I think that's kind of rare. I've heard the PCM's interchange between 99 and 03, but the salvage yards swear up and down it has to be an 03 police car. Any other thoughts? Thanks for your help.