rattling noise from engine when accelarating

[emmydotnet]

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

[MikeTangas]

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.

[Rockman59]

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.

[emmydotnet]

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...