I have been trying to solve this problem. I am not driving my 745T this winter so its not really a needs-to-be solved asap problem which is a good thing. When i got to start my car, it fires up but there is a severe vibration. Everything shakes, engine a little, trans alot (M46 shifter goes nuts!) and the idle is around 400 if that, car almost dies, and i need to lightly tap the throttle (not floor it, light tap) to get the voltmeter to show the alternator is charging then the alternator works. No oil leaks/loss, oil is fresh as well. Oil pressure is at 50psi or so when cold. What is going on here? Is it some sort of driveshaft problem, trans mount problem (When i did the mounts....i jacked up the trans, maybe damaged the mount which was pretty new? But it did this even after the new mount, before motor mounts, just not as severe because it wasn't winter and cold maybe?). New engine mounts, fairly new trans mount as stated. New injector seals, intake gasket, etc.. Anyone have any ideas?

Thanks
Dan
88 745T M46 180,500K
96 GMC Jimmy SLS 4WD, 73k for sale
[all records since new, must sell!]