My 2002 F150 with 4.6L developed a miss, and the check engine light came on. Off to the dealer I went. He showed me that the screen on the inlet to the injector was full of RUST. Yes my fuel filter was replaced at 35000 last fall. He said that he has had a few come in with rust in the fuel system.Ford doesn't know where it is coming from. Any ideas?

 

Im not sure where it is comin from but a guy I work with had the same problem with his focus. He dropped the tank and cleaned it sealed it with some tank sealer replaced the pump and everything seems to be alright now. If your pump isnt already screwed I would suggest doing the same. Hope that helps.