Funny idling..

[will lam]

Hi

I have clk240 on a 03 with less than 100k ever so often when it's idling at the lights the rev slightly creeps up to around 600rpm and you feel the car vibrating slightly and then when you pull off it's fine. Drives fine etc there's no warning lights and the garage sys there's nothing wrong.

Any ideas

Thanks

 

[camerafodder]

That idling sounds low to me. I would expect 700-750rpm

 

[will lam]

That idling sounds low to me. I would expect 700-750rpm

Isn't that high as it's around 500-550 normal

 

[BlackC55]

I expect an air leak, air mass sensor issue or a lambda fault.

Needs proper diag with a Star.

 

[will lam]

I expect an air leak, air mass sensor issue or a lambda fault.

Needs proper diag with a Star.

Thank you.. What's a star?

 

[gIzzE]

A fixed luminous point in the night sky which is a large, remote incandescent body like the sun. But that's not important right now.

Star is the proper diagnostic machine that will tell you where your issue is.

 

[will lam]

A fixed luminous point in the night sky which is a large, remote incandescent body like the sun. But that's not important right now.

Star is the proper diagnostic machine that will tell you where your issue is.

Could any independent garage read it or just mercedes? It only does it sometimes and no warning lights at all

 

[C180CGI]

It should store any problems on the ECU. Not always do warning lights come on.

 

[gIzzE]

Could any independent garage read it or just mercedes? It only does it sometimes and no warning lights at all

You need an indy with Star Diagnostics, otherwise it will bring up random codes that will tell you your car is underrevving, which you already know.

 

[gIzzE]

If you put you location in your details people can help you easier with recommendations on where or who to go and see.