dplummer87

When i have my windows down, and i press the throttle about half way quickly, it sounds like there is a coke can rattling in my exhaust. You have to listen carefully, as it is very quick. Any ideas of what this could be? I maintain my truck very well. Oil change every 4k with motocraft semi syn, i mix up the fuel from time to time ranging from 87 - 89 to flex. (Flex is only a couple times a year) However, I dont really use any fuel additives...should i run a cleaner or something through it?

dplummer87

Dont quote me on this just yet, but i think it only does it when the engine is "hot". I'm about to head out for the day so Ill see if it does it when i leave here.

rick99601

just throwing out ideas..
i would get under the truck listen to see if the noise is coming from one of the cats. my fathers '88 grand marquis made a sound like youre describing and thats what it was.

granted, it could be almost anything.

i sort of have a rattle like that but its only audible stopped such as at a light, if i put it into neutral the sound goes away.
i think my problem might just be a loose heat shield.

azmidget91

could be a loose heat shield, could be the exhaust rattling on the trans crossmember, could be a piece of you cat broke off inside and is rattling, could be a broken weld in the muffler...........

awheelterd

i had the exact same problem and it was my exhaust. do you have an aftermarket exhaust system? i have a banks cat back of some sort (po put it on) and i had a loose clamp. i tried to tighten it up but the u-bolt sheered off so i put on a big hose clamp as a temporary fix and its still holding up fine. i need to replace it with a real clamp tho.

dplummer87

Ya i have an after market exhaust. Only does it when hot. Doesnt do it if I rev it in neutral. Ill check the brackets under there...Any other ideas?