1998 Ford Expedition V8 Two Wheel Drive Automatic 145000 miles
My 1998 Ford Expedition, 5.4L was running good but idling rough. I was getting codes P0171 and P0174 from the ECM. Found the hose to the pcv valve was nearly ripped in half. Replaced that and it seems the problem is solved. Will the check engine light reset itself or should I have it manually reset.
Things I have done since the check engine light came on:
Changed EGR valve
Cleaned all EGR connection points
Changed EGR sensor
Changed all spark plugs and #1 coil (tested bad)
Changed pcv valve and hose
Changed air filter
I am hoping this will solve the emission problem so I can pass inspection.
The light will eventually go off, but it will take about 50 drive cycles if nothing else goes wrong. If you don't mind reseting your clock and radio stations, you can disconnect the negative battery cable for 10 minutes. The vehicle may run funny for the first few miles while it relearns all it's operating strategies, but it won't hurt anything.