I need your help guys.

If I'm not mistaken, the engine on my car is the same as the ones used in the C220.

Anyway, here's the problem:

Every now and again the idling drops to about 450-500 rpm.

This does not happen when the engine is cold. Actually the problem will only appear after about a few minutes of driving.

Sometimes once I start accelerating again and stop, it's back to normal - about 700 rpm. But sometimes it still remains low. There's actually no patern at all. But definitely a day won't past without the low idling happening.

I've tried putting an injection cleaner in my tank & filled it up (2 times), thinking it was just a blocked/dirty injection. The tank is now half full from the last & 2nd fuel fill and did not notice that much change. Maybe just a bit less frequent than before.

Can someone pls. tell me their expert advice & diagnosis on this problem?

I can have an MB workshop look at it but I'm a bit apprehensive that they might give my false and blown out diagnosis just to rip me off. Atleast if have more information, the less likelyhood that they could bull---- me.

Pls. help.

Thanks