I have a 1993 300E 2.8 with 97,000 miles. I recently changed the drive belt at the dealer to reduce engine noise. Since then, on occasions (mostly when the engine is cold), my RPM at idle speed surges up and down ranging between 500 and 750rpm. In addition, I have been having problems with the acceleration. I have to floor the gas pedal and shift gears down to get a decent acceleration and it still takes few seconds before the engine responds. My gas consumption sits at 22 miles per gallon (if this helps). Also, on a couple of occasions, few and far in between, after backing up, when I shift to drive, the engine shuts down. My dealer said that most likely my air pump is bad. It is not pumping the right amount of O2 into the engine ... the cost: $850 for the pump and $100 for labor ... before I go ahead and spend this kind of money ... I would like to make sure that the symptoms are consistent with a bad air pump diagnosis ... could this be due to old spark plugs ... I have not changed them in at least 40K miles ... please help ... this was such a wonderful car to drive ... I miss my responsive engine!

[This message has been edited by George (edited 05-02-2000).]

[This message has been edited by George (edited 05-03-2000).]