thanks for the clarification. my car shook in drive also. but i think i just might have lucked out on finding the solution to my problem - still cant believe it though! the ignition wire to the 6th cylinder was simply loose and upon getting hot, the spark wasn't going across smoothly. wonder why none of the mechanics didn't catch this simple loose contact! the car is now not going beyond about 85degrees and is smoother. i hope this was the only problem, i guess time will tell, but i sure am excited for now!

had a brainwave for your problem.......when i bought this used car, it was shaking very badly when i put it in gear. turned out that the coupling / mount / o-ring on the axle was cracked. i remember seeing two of these circular couplings - one in front and another one at the back. i think there's also a mount sort of a thing toward the rear of the drive shaft. you may wanna lift the car and inspect these items for cracks, these things look very flimsy to begin with.

good luck