Does anybody know what the engine is doing to itself when it goes in the limp home mode. I got the wrench light on my dash the other day and it seriously affected performance. When i restarted the truck it was gone and performance was back to normal.

 

That's your ENGINE FAILSAFE MODE "limp-home"
page 77 in your Owner's Guide

 

I suggest you take it in. It will get worse. They will end up replacing the throttle sensor which should fix the problem. It is a very common problem with the 04 F-150.

Philip

 

On mine, they only reprogrammed the PCM. No parts were replaced. It's been running fine ever since. You can read the entire saga at these links:

Part 1
Part 2
Part 3

 

Reprogram the computer? Y?

This tells me that the computer is changing its programming from field sensors or it cannot hold the programming, I.E. bad computer.

The feeling you get when your 54000CAN dollar truck with 7000kms on it brings up failsafe check engine lights and runs like crap is unable to be described!!!!!!!

OH and another thing, it brought up the ABS light as well, so i got under the truck for fun and look at the wiring on the abs, there is no electrical wires going to the rear brakes, just brake fluid and hand brake FYI

 

The problems you and others are having with their 2004 F150 are the exception, not the rule. Thousands of 2004, F150’s are trouble free for every one that has issues.

(my unprofessional opinion aka speculation)

 

The lamp means you've got a fault in the ETC (electronic throttle control) system. The PCM will default to a limp home setting, letting you drive the truck up to 60 mph if I remember right. That way it won't slam wide open or closed.