I have a 2003 crown vic (it was a police car at one point) and recently when i accelerate, usually between about 20-30mph, there is this metallic rattling sound under the car. The last time it did that, I got the oil changed (about 4 weeks ago) and the sound went away. However yesterday it started back up again. I figured that maybe my car is burning oil but when i checked the levels, it looked fine. The oil didn‘t look contaminated either, at least not as far as i could tell. Any ideas where to go from here?
Rattles can be easy or hard to locate. Once found a fix is straightforward. Eg catalyst brick breaking up ? Failed / broken support bracket? It's very unlikely an oil change would correct such a fault but there maybe a heat shield? That is near that was fixed and has come loose again.? We really need to get under car and have a visual look and wiggle and shake test by hand to ascertain any potential issues giving rise to fault described. A garage can do this as car lift makes it easy.
Check for loose heat shields around the catalytic converters. Remove all the loose ones.
