C-Class rough idle

[jimbob35]

Hi, im after a little advice on my issue. It runs beautifully when cold, and when warm, it runs to 90 degrees and stays there comfortably. But after a long-ish journey I start to get some weirdness..

First issue I get is the idle starts to rise, it goes to 1500-2000 ish. This can be remedied by turning the AC on! It settles to a regular level then..

Second issue comes after the first issue (today it occurred after some energetic driving, but in the past i've not found a way of replicating it), and the idle drops to maybe 500-600. And the car shakes very noticeably, it sounds like its struggling to stay running. It drives and revs perfectly, but will not idle.. It never stalls however.

Third issue (may not be an issue!) the car will not rev past 4000 when stationary, but goes all the way while driving.

Any help on these would be much appreciated, thanks.

 

[jimbob35]

I've just read on another post about a leak under the air box, but im not sure how to remove the box, seems to be a million things connecting to it.. Is it easy-ish to remove?

 

[BlackC55]

The first thing you must do it to get the codes read by a Star diag machine.

 

[markjay]

Do you have access to a code reader?

 

[markjay]

The first thing you must do it to get the codes read by a Star diag machine.

Beat me to it

 

[jimbob35]

I can get the codes read, sure.

I'm guessing by that response that it could be one of quite a few possibilities?

 

[jimbob35]

Eek. Engine management light just came on. Won't be able to get it to a garage until thurs, and have 200 or so miles to do until then..