C63 misfire maybe?

[Macka1]

Hi all,

Recently bought a w204 c63 with 34k on the clock. over the past couple of weeks of ownership i have noticed a bit of hesitation in idle when the car is in drive and you let your foot of the brake without any acceleration so the car is just moving under its own power. it can also be felt through the brake pedal sometimes when sat in traffic.

any ideas what this might be? the past couple of tanks of fuel have been standard unleaded due to there being nothing else available, could this be the issue?

Any help is much appreciated

regards

 

[Robdata]

Whants 98 octan. Look at fuel cap

 

[adz87kc]

The car should run fine on 95 albeit with reduced power due to the timing being retarded.

 

[PobodY]

The car should run fine on 95 albeit with reduced power due to the timing being retarded.

This.

I think the hesitation is normal behaviour from the box; doesn't it go in to a pseudo-neutral to save fuel or something, and the hesitation is it reengaging the gearbox? - Mine does something like this too; sometimes you take your foot off the brake and it doesn't start creeping forward (and before anyone asks, no I don't think it's brake hold because that's not a feature of a W209).

 

[Macka1]

This.

I think the hesitation is normal behaviour from the box; doesn't it go in to a pseudo-neutral to save fuel or something, and the hesitation is it reengaging the gearbox? - Mine does something like this too; sometimes you take your foot off the brake and it doesn't start creeping forward (and before anyone asks, no I don't think it's brake hold because that's not a feature of a W209).

Thanks for the response, does it judder a little. It can't be felt when I'm driving normally. Just when I come to a stop or I'm just setting off..

 

[bazzabear]

I think it's just the auto taking a second to decide whether to stay on neutral to avoid stalling, or engage the gear to allow you to crawl along.

 

[PobodY]

Has the gearbox fluid been changed? Old, dirty fluid might explain sub-standard behaviour from the box.

 

[Macka1]

Has the gearbox fluid been changed? Old, dirty fluid might explain sub-standard behaviour from the box.

There is no paperwork to suggest it's had it done. It has had a service pack from new. What interval would this be at? Last service was last month and it was just an oil and filter. How would I check what else has been done?

 

[aquanaut]

There is a transmission and ECU update available from the dealers. Get this plus gearbox oil and filters

 

[Lee C63]

Had the same issue on mine a while back and it was down to the spark plug gap needing adjusting.