my mercedes idel is not running study ,it is bouncing around,can please help.

It could be many things, unfortunately and without experiencing the problem first hand or being able to do some basic diagnostic tests its hard to say. It could be a problem with the idle control motor, a vacuum leak or many other things, impossible to say without being able to do basic tests.

Need to clean the throttle body and see if it helps. We're in Dublin or Vallejo if you need some more help.

Most common cause would be a vacuum leak, secondly a idle control motor. If you do not have the equipment or know how this would not be a good vehicle to learn on. The two mentioned possible causes are the most common, but there a a lot more possibilities. We specialize in diagnoses Contra Costa Smog. If you have failed a smog check you may be eligible for C.A.P. money of $500.00 towards your repair. 925-947-2555