Is200 Erratic Fluctuating Idle

[bashdem]

Hi

My 1999 is200 has started idling a bit funny lately. It fluctuates below and above 500 rpm but never high above 1000 or low enough to feel like it's stalling.

At the same time the lights dim very slightly and then return to normal. It happens a couple of times every few seconds.

It's a little unresponsive to pull away but nothing major. The general pull of the car at normal driving speeds isn't what it used to be but again, nothing majorly slow.

I sense the slight erraticness when driving, it's not massively noticeable but I'm not sure the issue is limited to just idle speed.

Any ideas where to start looking for the cause?

Cheers in advance

[bashdem]

EDIT: It actually idles between 500 and 750rpm. I've also noticed it's more likely to have these little surges once the engine has warmed up.

Any ideas anyone?

[matt-c]

Check the Battery health, and it's earth(s) to start with