My check engine came on today when I punched it an when I slowed down truck turned off said engine fail safe mode any ideas what it could be

 

If you're in "safe mode" (also known as "limp home" mode), there must be a code set. Get it read and post it here. Most auto parts stores will read your OBDII codes for free.

 

My owners manual states that the "fail safe" mode is an over heating condition where the computer fires alternating cylinders causing the engine to run rough. The alternating firing causes the "dead" cylinders to draw in air & fuel, but not fire; therefore, cooling the engine. Even then, if the temp gets high enough, the engine will shut down automatically. Sounds like that is what happened.

Was your problem an overheating condition?

 

Take buckos advise and have the code read and post the code on here and we can help you.

 

No it didn't overheat

 

I will post the codes tomorrow

 

Same thing happened to me! Turns out it was a broken spark plug so it wasn't getting fire.