Power steering
 

I have a 2003 E320. Power steering just went wacky on me. When I am at idle or aslow coasting speeds, the power steering stops working. But if I just barely touch the gas, it comes back. loose belt, low fluid, or?????:(

Sounds like your pump is getting a little week. This car uses a synthetic p/s fluid. I have seen the fluid get very thin and cause this. I have had some luck with flushing the fluid with this problem. Just suction the fluid out of the reservoir, refill it and start the engine. Repeat this process turning the steering wheel lock to lock a few time. Run 2 liters of fluid through and you should be good to go. Even if you need a new pump it is good to replace the fluid. Try this first it should feel a lot better.

Yeah, it was the pump. Tech says very rare on this model of car. of course other than electrical and torque struts, that is what he always says. Had to ship from Cali, nowhere in stock (because a failure is so rare), expensive repair.

I would flush it first. It fixes them.