He's to start this thread off , my brothers friend drives a 94 ranger POS by the way , and since mine is a 94 he thought his key would work in my f250 . And for the past two weeks since it's happened I'm getting this faint knocking/raddling noise that is consistent I can't pin point were it's coming from to me it sounds like it's in the serpentine system . I'm not sure if #8 injector is sound is finally manifesting now to where I can hear it but my starter was hung up the whole time my truck was running with his keys in my truck . Any help would be appreciated!

 

Use a piece of garden hose a couple of feet long to listen for the noise. You may be able to pinpoint the source. Couple of possibilities, (a), The starter was damaged during the key swap fiasco. (b), A component near the front of the engine is failing and you didn't notice this noise prior to the starter key swap deal. Try to determine the source of the noise and proceed from that.