I have a 2009 5.4 motor and the check engine light is coming on and off for months. I've noticed that once my fuel level gets down to less than a 1/4 of a tank the check engine light comes on. Once I fill it up it goes off, wasn't to worried about it. Now when I fill it up it comes on until I burn off about 20-30 miles after topping off. So when I'm low it comes on or when I'm topped off it comes on. Everything in between goes off.

I've read a lot about the fuel rail sensor issues on previous models but can't find anything about 2009, can't even find that part. Did they change it to another location or part? If not where is located? I also looked at my fuel drive module looks to be ok. Anyone else have this problem? Just read about the fuel pressure sensor located on the tank, but wanted to check before I dropped my gas tank.

 

What is the DTC.. you should have a fuel rail pressure sensor.