I have a strange vibration from my 99 acura cl in every gear right at 1600-1800 rpm, the car is a manual and its been happening from around 50k miles now it has 130k. I dont know what to do any more, exhaust has been replaced(cat back), front motor mount (torn) replaced. I Can not find anything that is loose or that would cause noise. It seems like the whole engine goes into this vibration and it just rattles the whole car. The car has no fault codes and i really have nothing to go on. The car does seem to have a lack of power around city driving,mainly when pulling of from a stand still(low rpms) but on the highway it feels great. Does any one have any diag tips? or if i should check something.?

 

im starting to think that the cat is loose internally.. but wouldn't that thing fall apart in with in 80k miles if it intermittently rattles.?