intense vibration at idle (617) Help?
 

I have an '84 300cdt. Since i have had it, it has always run good and smooth except When it needed a rack damper adjustment and even then it was just a slight "wobble" at idle. Recently, it has developed an intense vibration when at idle speed. Strong enough to shake the hood, bumper, steering wheel, the corner lenses actually shook loose, etc. With 310,000 mi. on it, i'm not sure where to begin. any input would be very much appreciated.

Engine mounts, then trans mount, then engine shocks.

Jim

I figured mounts and shocks but was puzzled by the fact that the vibration started overnight. It was running smooth, then one morning i started it up and there was the vibration.

Back off all the injector lines one at a time to verify you have not dropped a cylinder at idle. If you find one that does not make much difference check the valve clearances if long overdue.. Since the marker lights are shaking loose from the fenders it sounds like more than a gradual motor mount deterioration. Maybe a totally broken motor mount though.

I operates OK at speeds other than Idle?
Some other possibles: air leak or some sticky injector pintals.

Did you replace the RD bolt?

If the motor mounts have sunk til it is metal to metal it will sound like someone is working on your frame with a jackhammer.

Tom W