terrable idle/runs great at high speed
 

83 300 d turbo 5 cyl think all of this model was-shakes the whole car at idle ,but runs great on road not good on diesel think it may be in pump front 2 cylinders , have switched injectors around have 5 extra used but suposed to have been cleaned -when checking at base of injectors,with infared thermometer the front 2 are not as hot as the others who has ideas or has experienced same thanks=added = have found out rack damper bolt can cause this{informant said shake like a paint shaker} so try that next=located rear of inj,pump ,was not it checked valves,not that!

Check with your infrared gun at the exhaust ports, the cooler ports would be the first ones I would check. You can also crack one of the injector lines at the injector, and see if the miss gets worse or stays the same. If it stays the same that is the cylinder you have the miss in. it could be anything from a weak injector to low cylinder compression.
Good luck

trying to thank every one very apprecative for all answers/and your time,due to motor mount answers know the problem drivers side mount is metal to metal,found some for $9.99 ;$5.50.shipping but their site was some what missleading got 2 transmission mounts=it said motor and transmission mounts,,to me that sounds like all three are the same ,not so ,or one size fits all,so going to send one back,use one/get 2 MOTOR MOUNTS,then be in hogg heaven,can drive as i wait for mounts cut strips from old tire stuck in ,does not rattle,we have 2 trucks and van but ths is my favvvvoooorite one = will be posting more later still have several issues , 68 yr ols retired draw s/s so have to do a little at a time thanks again Sonny Boheler in Chester S. C.