190E won't run below 3,000rpm
 

My boyfriend changed the master cylinder in our 90'-91' 190E and after that, the car doesn't stay running below 3,000 rpms. We have to keep our foot on the gas. He's changed everything that he knows to change (that doesn't cost our life's savings). Any advice? The master cylinder itself couldn't have been the problem, but maybe he messed something else up while he was in there?

Hmmm. That could be a problem. Running that engine over 3000 rpms continously is not good for it at all.

Perhaps some wires were loosened? :confused:

check the vacuum line that runs from the intake to the brake power booster (the big "container" that the master cylinder attaches to). If this line is disconnected, there will be a HUGE vaccuum leak, and the car probably won't idle at all.