rattling noise from engine when accelarating
 

on my 1991 560SEL, i just noticed some rattling noise coming from the engine when I accelarate, particularly when I accelarate hard. there is no noise at start it up nor on idle. also, i do not hear this rattling noise when i press on the gas pedal when car is on park.

anything i should be checking for?

thx,
emmy

Air cleaner mounts (are they intact?) or motor mounts could easily cause a rattling sound on acceleration. If it's the motor mounts, the rattle could be the fan hitting on the shroud, check out the fan baldes and condition of the shroud.

That "rattling sound" might be spark knock. Are you using good gas....as in Premium? How about your timing? Just a couple of things it could be.

i found a small tubing that was disconnected. This tubing is the one that plugs into a bigger hose (..hose connected from under the aircleaner to the right side valve cover). i plugged this small tubing back and it appears to have solve my problem.

thx for the inputs...