i have a 97 f150 4.6 L after driving 10-15 mins the engine starts to chatter sounds like a diesel only when i accelerate and there is a load on the engine. when idleing it does not make this noise. Does anyone have any idea what may be wrong?

 

Plugged fuel line, restricting higher flows under acceleration and load? I'd replace the fuel filter, but you need a special tool to do that. They're like $10.

Is your check engine light on? If so, pull the codes and that can give you a place to start. I've heard sometimes codes can be stored without triggering the CEL, so maybe try it anyway.

 

im not losing any power under acceleration, but my engine light is on...