My 01 has started making a rattle that sounds like a diesel during light throttle. It does not do it in neutral and starts slightly when put in gear. It is hard to pin down and seems to be rpm related. When I let off the throttle it stops. Sometimes it sounds more like a ticking at idle (like a loose valve) but it stops when letting off the throttle and when in neutral. I have to turn the radio way up to mask it ans it sounds like an old chevy with noisy valves in the cab when driving. I have a loud exhaust and can still hear it so this is not a sutle noise. The truck runs fine. I have read about an EGR noise so I will try that test with the vacuum hose later. I was worried about the trans or converter as it started when in gear.

 

Well My problem which otheres have had is a rattle noise right before a shift under 1/4th to almost wot throttle. , it doens't make any rattle noise besides just before a shift.

Shane said he had the same problem but I don't rmember what he said his ford people did to fix it? maybe he can tell us.

 

I've had the same noise going on 1 1/2 years (since I installed my LT's). I've checked the header gaskets, and plugs but nada. Too me it's almost like you can hear the pistons during throttle. Good luck on finding the problem and let us know.