I have a 2006 Ford Expeditions - 5.4 @ 134,000 miles
About 8 months ago it ran rough and quit. Started it and it ran fine for another month. It would kill periodically here and there. About 3 months ago it began going into "engine fail safe mode". I brought it in and NAPA said to clean the max airflow indicator. I did that and it ran well for another month. Then full "engine fail safe". I was told to replace the spark plugs and coils - I replaced all 8 (major job...) Truck ran well for a month and "fail safe mode" came back. Code told me to repalce the max flow indicator - did that. Two days later, same.. Next code said to replace thottle position sensor - just did that and the same. Truck just started again and ran well for about 3 miles and then went back into fail safe again.
I'm tired... need someone to help me as I'm growing tired of the wormhole.
Any more ideas?

 

I don't know if this suggestion will solve the problem, but it's worth a try.
Actually there are two things you might try.
Remove the negative battery cable for 30 minutes (go have a cup of coffee) and reconnect it , sometimes gremlins leave.
Also remove the plug in wires on the alternator and take a test ride.
Problems in an alternator can breed those darn gremlins.
You may get a charging indicator lite, but you will know why, and then just reinstall the plugs.

 

Wow, so far after the 30 minute unplug, it seems to have worked!! Thanks Hanky! Will keep u posted