Hi, I am having a problem with my truck and was wondering if i could get some advice? I have a 98 f150 with a 4.6 triton. when i'm accelerating, usually between 1500-2500 rpm, my engine will make this rattling sound like its running low on oil or something. I've put in supreme gas last couple times, didn't help, so I know its not detonation. I've got perfect oil pressure all the time, oil level is good, mobil 1 5w30. new spark plugs and wires. transmission level is good, so its probably not the transmission. only thing i can think of is something with the exhaust, like a leak or something. the exhaust is pretty new, only a few months (cat back). what do you all think? Thank you

 

check the heat shields in and around you cats, they're notorious for the spot welds breaking loose.

 

I had one of the cat ID tags rot off and lay on the heat shield making a TERRIBLE rattle. Just removed it and threw away. Saved me about $400! lol

 

Check your front sway bar link bolts. They link the sway bar to the control arms and are easy to find. Look in a manual to see where they are. One may have broke causing the sway bar to slap against the frame. I had one completely gone, and the other broken. This causes the sway bar to become loose with even one bar link broken. Also, they were pretty corroded from all the magnesium chloride they spray on the road in Colorado. OE bar links are about $20. Just an idea, could be a lot of things.