I have a 1986 560 sel with 250,000 miles and just recently it has been shaking pretty bad when stopped at a red light or etc. I was told it was the spark plugs but after I replaced them with Bocsh, the car still shakes when at stop. Would anyone have any suggestions about the reason for it shaking so vigorously?
Thanks

 

Replace the spark plugs wires my 560 did the same thing when i bought it. And yes you did the right thing getting the Bosch plugs also get the Bosch wires.

 

Would that have something to do with the battery?, usually if I havent started it in a bit it doesnt want to turn over, or is that just because its cold outside?
Thanks =)

 

The battery should not be the reason for the shaking. But if it is hard to start it may need charged if u dont run the car often.

 

well hard starting in the cold could have something to do with ya battery but that is outside the reason for your car to be shaking.
FYI A battery that is going bad usually becomes more apparent when it's cold.

 

could be alot of things.
plug wires. spray with windex check for arching.
plug wire ends. check with ohm meter should ne be more than 2 k ohms.
motor mounts with 120k hell just replace them
could be a bad injector do you have the old steel injectors of updated brass ones?
could be a lambda adjustment.
could be a vacuum leak is the trans shiftng hard ? check the modulator vacuum hose conetion ot back of intake manifold
cold be a fuel distrubitor pluging loosen 1 fuel line at a time at fuel distrubitor and tap on line check for bunch of crap coming out
well the list goes on you get the picture

 

I fixed that problem, Lugnut told me to check the plug wires to see if they may have been lose, sure enough one of them was.
Thanks

 

need electrical diagrm for 85 500 sel