1999 Ford Expedition Q&A
1999 Ford Expedition Question: Intermittent misfire.Stumble on acceleration,Dies,Various codes,No service light
Vehicle misfires sometimes,Occasionally dies Tach and speedo go dead will not restart until the key is cycled fully off then back on Odometer reads only lines until restart then quit working all together,Intermittent Heavy Stumble on acceleration not a misfire more of complete loss of power momentarily then comes back on. Set various codes for All the above sensors one at a time without check engine light. Has freeze frame data sometimes. Code and data clear on first key cycle. Crank,TPS,Knock,cam,and MAF sensors all test good. Battery 12.6 volts key on,14.2 volts running,Replaced coils and secondary O2 sensors, EVAP monitor will not set. Never the same code twice. All symptoms clear up for a day or two then come back one at a time never at the same time. Checked grounds and commons for voltage and resistance. I suspect PCM ground or PCM power feed. Possibly on the VSS circuit. Any help would be appreciated. Thank you. - AKnight1
Check power connections. With vehicle running start moving the harness until you find the gremlin. - Hal...
you could have a bad pcm - goodguy
Have you checked fuel pressure? What is the fuel trim? - tramies