hey im new here and i have a 1995 ford f150 auto 5.0 4x4 with a intermittent rattle sound only under a heavy load?

 

Check heat shield on cad converter. the clips rust out and let rattle . At certian RPMs can even sound like engine pinging . Give it a try I have to fix the one on my new truck. Good luck
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94 F150 XLT 4x4 SC LB Maf 302 E40d 3.55 rears

 

Is it at heavy load or at idle?

 

heavy load, and i removed all heat shields right after buying the truck. im thinking maybe a timing chain hopefully im wrong

 

If it was the timing chain you would be having way more problems than just a little rattle! hahaha
But seriously...on some trucks there are little shields that keep the plug wires from touching the headers where they bolt to the head. These can sometimes rust out and begin to rattle against the header.

 

I would guess pinging as my 302 does this as well under load. Try running some SeaFoam or other injector/intake cleaner through it. Or maybe fill up with premium fuel once, and see if it goes away.
Let us know how it goes.
Al