Acceleration problem on freeway
Took the car into service on Monday and just got a call back. Service department is claiming they couldn't find the issue, they reprogrammed the car and test drove it and it's fine. I'm almost sure this problem hasn't been fixed and worst part is that the problem will probably happen the next time I go on a road trip. Super frustrated right now...going into the service dep. my main concern is that they wouldn't be able to mimic the acceleration issue on command.
Car is at 6k miles.
Last edited by Fang88; Jul 1, 2015 at 02:42 PM. Reason: more info
Were you using the shift paddles? And perhaps something was stuck under the accelerator pedal? Just my initial observation.
I was not using the shift paddles. I thought maybe it had something to do with the auto-braking driver assist feature malfunctioning(was on almost empty road with no traffic) and i turned that off, but problem still persisted. Issue happened in comfort and sports mode.
Last edited by Fang88; Jul 1, 2015 at 03:01 PM.
Fang, are you certain you weren't experiencing the kickdown position on the accelerator? Did you "floor it" with some gusto?
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This guy's kickdown isn't working, and the car is slowly losing speed on the highway. Different car/technology, but same principle.
Last edited by CorradoJr; Jul 1, 2015 at 03:28 PM.
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I should probably show my service advisor this thread...
Last edited by Fang88; Jul 1, 2015 at 03:38 PM.
Try a few other things to see if you can narrow it down. Does it happen at a certain speed, when car is cold (not warmed up), etc. to help with the diagnosis if possible.
In the meantime, if it happens again, you can use the paddle shifter to request a downshift, which may override things.
Hope it gets fixed and goes away for good!
I had a similar problem last week. C220 sport manual
Engine slowed down from 70mph to a crawl, kept changing down gear but the engine just got more sluggish. It felt like the brakes were applied, no handbrake light though and no energy management light.
Pulled over and restarted the engine and it seemed to drive fine afterwards. No problems since but I have booked it into the dealer this Friday, will let you know what they say
I had a similar problem last week. C220 sport manual
Engine slowed down from 70mph to a crawl, kept changing down gear but the engine just got more sluggish. It felt like the brakes were applied, no handbrake light though and no energy management light.
Pulled over and restarted the engine and it seemed to drive fine afterwards. No problems since but I have booked it into the dealer this Friday, will let you know what they say

What it might be is a transmission temperature or temperature sensor related issue. When the transmission temp sensor detects a rise in fluid temperature above preset limits it causes the transmission to change down & increase engine revs & thus circulate more fluid via the cooler (transmission pump is input shaft driven) & reduces power until normal temperature operation is attained.
The temp sensor might be faulty or the TCU programming over sensitive.
Last edited by Glyn M Ruck; Jul 8, 2015 at 10:54 AM.
Interesting if temperature is the cause, would there have been an indication on the dashboard? I can't remember seeing any warning lights, but I was concentrating on getting out of the fast lane to the hard shoulder in peak traffic!
Fang88
The kick-down accelerator issue would only be for the automatic model wouldn't it, mine is manual?

Interesting if temperature is the cause, would there have been an indication on the dashboard? I can't remember seeing any warning lights, but I was concentrating on getting out of the fast lane to the hard shoulder in peak traffic!
Fang88
The kick-down accelerator issue would only be for the automatic model wouldn't it, mine is manual?
There would be zero dash indication. The ECU/TCU just handles it!.







