Have a 05 F-150 5.4 4x4 auto. It has gone into failsafe mode 3 times in the last week! Temp looks good although I have little faith in the idiot guages. I stop and cycle the key 3 times and everything returns to normal. Spoke to dealer service writer and he states that he has never heard of this problem!!!! I'm skeptical as I was told the same thing about my 6.0 Diesel and now I see them being recalled for all the same "NORMAL" issues that I was complaining about! Any info would be appreciated as I am meeting with the dealer service manager this coming monday and don't like to go to a gun fight with a knife!

 

Go directly to the dealer, do not pass go. This is not "normal". Mine did that and after the delaer reflashed my PCM it has not happened since. The failsafe mode will come on even if the engine is not overheating or what ever else it thinks is wrong. Good luck......

 

I had this same problem and the dealer reflashed the PCM. Problem reappeared 1 week later. As I understand, it relates to preventing a runaway condition or whatever with the 'throttle by wire' gas pedal system.

When in failsafe mode the engine runs rough with poor acceleration and the transmission shifts are not smooth. You will not see anything on your gauges. That's the first thing I looked at too!

In the end they found that the throttle body was malfunctioning and replaced it. No problems since(2 months now).

 

This is too spooky, I posted this same thing a couple years ago. My 05 kept going into Failsafe, new throttle body and reflash. Worked for a couple of years then it started again along with cam phaser etc. Got 08 ,same truck 5.4 4x4. Well guess what, Failsafe 3 times this week! It happens when I come off the freeway and am just cruising along. Shut truck off, restart and all is good, I will be going to see my favorite service writer soon. Have to take my camper shell off so they can fix the rattle in the power rear window also. Worse is the last episode happened when my wife was riding along, she already hates this truck because it does not have seat heaters!!! I love my trucks, have had 5 Fords since 96.