<IMG src=smileys/smiley19.gif border="0">I have had my 2003 C-230 for a year and this problem has been persistent. The car will hesitate while accelerating, as if you had taken your foot off the accelerator (but didn't!). It happens sporadically and usually when accelerating normally from a stop or a slow speed. I have taken it to the Mercedes dealership in north Houston, Texasthree times and theyintimate thatI am either lying or crazy. They say that they cannot find anything wrong on their computer and that they have never heard of this problem and that it must be something odd that I am doing with my feet!! I find it hard to believe that mine is the only C230 experiencing this problem. It is not just a mechanical issue, but also a safety issue as cars behind me are accerlerating while I experience this "pause". The hesitationlasts a few seconds, then the power comes back to normal. Anyone have any ideas as to what might be causing this problem?

 

you are not alone my friend. i've had the same exact situation. the first time it happened, the dealer had it for a week trying to look for it. they figured it was some error codes they resetted. then after a few days i picked it up, the hesitations started happening again. i took it to the dealer, had a technician ride with me, and of course it did not happen one single time. but i left it there anyway and they had it for about three weeks because they wanted to make sure that it was all okay. they replaced little parts here and there (sorry i can't remember what they were, some were sensors) because everytime they thought they figured it out, the hesitation comes back.

now i've had the car back for almost three months now. the hesitation is still there, but since i do not use the car often, i do not experience it everyday. i switched my two cars every two weeks. anyway, the hesitation is more obvious when the car has travelled a bit, maybe more than 10 miles, or when the car's been running more than 30 mins. i have called the dealer, but they advised me to take it back when the hesitation happens more.

the hesitation is like a sudden loss of power. it also happens when in the freeway on cruise control, the cruise control shuts off. it happens when accelerating from a stop on an intersection, really dangerous when someone behind you assumes that you will continue to speed up, then ends up braking because your car suddenly wants to fall on it's face.

yes, it sucks. i'm hoping when i drop it off again at the dealer that they have found this problem to be a defect that they can now fix.

good luck.

norm

 

I have the same car as you and ive never had this problem but I did have this problem on my mom's S500. It was an accelerator sensor in the gas pedal that wasnt triggering on time. Thats the problem dude trust me. Go to Mercedes and tell them that thats what the problem is and they should take car of it. Hopefully Im right here. Let me know how it goes. - John

 

the PEDAL VALUE SENSOR is losing it's signal to the ME control unit. i have replaced several of it on 220 models but not on C class yet.

it is a service measure (recall) item and no fees will be collected.

 

Thanks for the info. I've got this problem on my C270. It came back from the Mercedes garage 'fixed' last week but it happened again. My hesitation lasts for a few minutes and can be quite dangerous, so it went in again a few days ago. I'm going to fax this thread to the garage and tell them to replace this sensor.

 

I thought I had the same issue on my 02 C230, but after couple of days of worry and investigation I discovered it was the brake pedal! When you just rest left foot on the brake pedal or touch it, it will cut off fuel delivery to the engine, as you were braking. Since then I am paing attention to my left foot and it has never happened again. Hope it helps

 

Did anybody experience little rattling sound in the front part of the engine when pressing lightly on the accelerator? Or releasing it to idle? It happens when parked or driving, whenever I press accelerator from idle (just for a second) or when rpm is going down to idle... just before it reaches idle I can hear the rattle (like engine's snoring). I was told by MB mechanic it is normal, but I did not have it, before (now 43K miles), then they said ...camshaft position sensor - I replaced it, but the "snoring is still there. Any experience with the issue, or any advice...Thanks.

 

I just purchased my 2003 MB C230 Kompressor Automatic Transmission three months ago. I've put in exactly 2300 miles and just last week I started to notice the car's hesitation when accelerating. The frequency of the hesitation or loss of power when accelerating is unpredictable. When I step on the gas pedal from a full stop, the car feels like it starts from 1st gear and then skips to 4th or 5th gear - hence the sense of loss of power. It doesn’t happen all the time, but when it does happen, it really sucks! And often times, it is of a safety concern because sometimes I rely on the responsiveness of the acceleration to avoid accidents – if you drive in Los Angeles you know what I mean.

I have had many years of experience with cars and my common "dude sense" tells me this is not a transmission issue. Of course my dude sense can be wrong. But, I have inspected everything about the transmission and it really does not look like it is a tranny problem. There are no sudden jolts when changing gears from drive to reverse to neutral or park etc... Also, the transmission works perfectly fine most of the time and there are no signs or leaks or any sort of noise from the transmission. It really feels more like some kind of technical problem with the accelerator.

According to this message thread, it appears that I have the same problem that others have had regarding loss of power and hesitating acceleration. The last posting mentioned "rattling". I actually also experienced the same thing. And I think I know why and where your rattle is coming from. I think the rattle feels more like a bunch of marbles grinding or bouncing off each other in a box, sound right? I think this is because the transmission is changing gears to 4th or 5th gear when it should be at lower gears 2nd or 3rd gear. Not following? Just look at it this way, if you drive a car with manual transmission, and you are at a full stop, you start from 1st gear right? Then 2nd gear, then 3rd, etc... Instead of going to 2nd gear, you change to 5th gear accidentally, what happens? It feels like marbles grinding under your car right? It rattles right? That's because 5th gear does not work at an rpm and speed that is too low.

Now back to my problem, I really think it is the accelerator making faulting signals to the tranny. The engine and the tranny are thinking they are at a higher rpm and speed. I don't want to assume I’m right (although I am always usually right) so I want to ask your "dude sense" or if you have had the problem fixed, can you tell me what you or they did to fix it? Most importantly, if this is a universal problem, I will hope that most of you know this should be a “recall” mechanical and safety issue, we should report it. If enough of us complain – they will listen. I’m just sayin’…

I really like to hear from you. Any advice or repair suggestion will be very helpful. Thank you for your time.

 

Well, the "rattle" comes from the front of the engine and happens only when accelerator pedal is pressed down the released... no drive is engaged. The car is standing or moving, it makes no difference. In my case it's been like that for over a year and so far nothing happened, so I just take it day by day.
As far as loosing power ... as I mentioned it was all due to the fact that my left foot was touching the "brake" pedal. Mercedes has this feature, that "cuts off" fuel delivery to engine when braking, and it takes just a tiny movement of brake pedal. Once I noticed that, over two years ago and paid more attention to my left foot (where it rests) the "loss of power" never happened again. Hope that's what you have ...good luck

 

I would suggest to check for fuel pressure. By checking your fuel pressure, you're diagnosing fuel pump, fuel pressure regulator, and fuel leak down rate. I have replaced some fuel pumps on those cars, and repaired some electrical wiring at the pump, so check that carefully.