Date: Fri, 21 Sep 2007 17:19:41 GMT From: Doug Schwarz <seenospamfor.address.edu> Subject: Intermittent engine vibration
I have a 1995 900S with an intermittent engine vibration. It appears to be related only to engine speed and it comes and goes. Here are my observations: 1. I notice the vibration mainly through the gear shift lever and the gas pedal. 2. When it first started it would exist for an entire trip and then be absent for another entire trip. Now it seems to start and stop during a trip and the amplitude varies, i.e., it's not the same intensity all the time, but you definitely can notice when it's there and when it's not. 3. It feels and sounds a bit like a hole in the exhaust system, but the character of the sound does not change with the throttle. It will be present at idle. If I get up to speed, press the clutch and then rev the engine back up to the cruising rpm the vibration feels exactly the same. As a result I conclude that it's not related to the tires or other drivetrain components after the clutch and also not a hole in the exhaust system. 4. It seems to peak in amplitude at about 3200 rpm. 5. The other day I did quite a bit of driving around town on a hot day (about 82 deg. F) and the vibration was absent so maybe it's temperature dependent. I called the local dealer and the service advisor said he'd never heard of anything like that before. I didn't get a chance to talk to a mechanic. Any ideas? Thanks! -- Doug Schwarz dmschwarz&ieee,org Make obvious changes to get real email address.