I just Purchased a 1993 E300 , when i come to a stop, the rpms jump up to about 2000rpm and it sounds like it reving over and over what could it be?????

 

I think the ICV (Idlle Control Valve) is bad.... and may be some vacuum leak

 

Thnaks Leon I'll have that checked into .

 

maybe spark plugzzzzz

 

well thats cheaper to replace than the idle valve

 

battle cat spark plugs will not cause this. idle speed valve over voltage protection relay and maybe a purge valve sticking open. i have seen lots of purge valve cause a problem like you stating

 

Right, I was thinking 'rough idling,' Ma bad.

 

It's gottem worse . now the car will stay running as long as im moving over say 30/mph and i can feel it jump while driving , " Car Speed's Itself up" and today sitting at the gas station I was in drive with brake on and my car continued the dreaed idleing and then RPM dropped and car turned off. this happend 3 times. SO Now im haveing a hard time keeping the car running at a stop .....

 

I have a 1993 300E as well with a 2.8 V6,,, the idle is doing the same thing, when i start it up in jumps from 400RPM to 800RPM and goes back and forth... The check engine light is on, however I'm not sure how to check that... anyone know?

 

the thing is that there are no other indicators in my car , as in no check engine lights or anything.