I have a 90 300 e 4 matic with 93,000 miles on it. I have been experiencing this weird vibration from the steering wheel when i make a tight turn at very low speeds. I had it in for an oil change and noticed the CV boots were both ripped and grease was everywhere on the bottom of car. I had both axels completely rebuilt thinking this was the source of the problem. I needed the new boots so i figured i would rebuild them anyway. Still the problem is there. My mechanic said the front end components are fine. This problem only occurs when the car is warm. Only after driving maybe 5 miles or more. First thing in the morning the problem does not exist. My steering pump looks to be fine, not leaking fluid. Could this be the problem? the car looks like it has the original plugs and wires, im not sure. It starts a little rough sometimes, but it runs great. The idle is around 600 after it is warmed up. maybe this is too low? cuz when making a low speed sharp turn it seems like the motor wants to die. In the morining when the car is cold, the idle is around 900, and the problem is not evident??? Any ideas????? if the plugs were bad, could this cause the idle to drop at very low speed turns?

Can you describe the "vibration" in more detail? How fast are you going?
Also, I thought the front axles were not rebuildable and you had to replace them with new.

Well, my mechanic had them sent out to get rebuilt. They are rebuildable, cuz i got a bunch of quotes from differant mechanics. The vibration happens at very low speeds, like if im making a slow "U" turn. I can feel it through the steering wheel. it feels the power in the steering is going in and out. Can a pump be bad if it doesnt leak, and works some of the time?

Is the vibration "pushing" the steering wheel? Often when the pump malfunctions the steering wheel will vibrate/get pushed.
Although it sounds like a possible faulty CVB joint, too, which would probably feel like a transmitted vibration with no "pushing".
Is there any noise with the vibration?

there is no noise with the vibration. it feels like the " power" in the steering go out and in, like pulsates. i just had the cv joints rebuilt. Both inner and outer axels. I dont know what you mean by pushing.

it only happens when the car is driven a few miles. First thing in the morning ut is smoothe as silk. Can a pump fail once in a while? or is it either good or bad?