HighEndOne

Hello Folks,

I have a 2002 CLK55 with just 29K on the clock. It has been flawless until now. The car was built in Augst 2001.

About 18 months ago in warm weather the throttle just stopped resonding. I could press on the pedal but there was no response, or a delayed response. The car would idle fine and start up fine, but there was no "go". After a restart all was normal. No CEL and no further trouble.

Well the issue is back this week and it's winter here. If I really hit the pedal it will slow down like it is gas starved or something. Also, I notice that it seems to happen coming off of a corner (the very first time was the same thing). It will continue with the delayed throttle (I mean it takes several seconds to spool up) and then the power returns, but not totally.

It seems like the throttle is in slow motion. It starts and idles fine however and it did light up the CEL, but that went off after a couple of restarts.

I cleaned the MAF today with the CRC spray, and threw in some fuel system cleaner to absorb any water in there, but there is no change. I read that the MAF can go bad over time with no real relation to mileage and all the parts (MAF, TPS, CPS) are orginal, except the plugs and wires.

I can do the labor myself and I am tryng to decide what to replace first. Any hints or suggestions?

Marcus are you out there? Thanks.

sosh

To me it does not sound like any of the items you mentioned. The only way to tell is to have it diagnosed with the Star system which means a trip to your dealers unless you just want to throw parts at it. A proper diagnosis is of great importance when you need a problem like this solved.

Jon2007E63P30

I am sure that one of the multiple threads you started will get you an answer.

I know, that is a "jerk" statement, but you certainly did not need to start 2 threads on the PL.

TMAllison

Its not going to be the MAF or the CPS......I'd pull the code if it were me; but if we want to play 3 guess's w/o that data, I'd guess batt voltage first.

I reserve the right to be wrong though.

TPS is not a high fail part BTW.

Ausmbtech

That sounds like your accelerator pedal sensor has failed. If it feels like the throttle is in "slow motion" and won't go back to normal without a restart then that'll be your problem. The W208 has the sensor in the engine bay at the end of the accelerator cable, the W209 has it in the pedal itself.

It will throw codes, so you can check them.

HighEndOne

Folks,

Thanks for all the help...

The consensus seems to be the MAF, so I will be staring with that.

Based on the age and the tendency for it to go bad at any time, I figure I will start there. The worst case is that I will have a replacement part that I can tuck in with the spare tire for the day when it finally does die (in the middle of nowhere).

If this does not do it, then it will likely be the TPS, AKA accelerator position sensor.

I will post the results of the MAF swap ASAP. Thanks again to all…

HighEndOne

First, thanks to all for the help here...

OK, so after cleaning the MAF the problem persisted.

Step one was a new MAF which improved the smoothness of the engine idle but did not fix the throttle problem. After the 20 minute MAF replacement (never pay a dealer for that job) the CEL light came solid and threw a P0120 code which points to the TPS.

So back to Autohaus for that part (TPS). After another self-service 20 minute replacement and an ECU reset the CEL is off and the car is running well.

I drove it for about an hour the other day and I guess time will tell if it's really fixed, since now it's cold and snowing where I am and this car never goes out in that kind of weather.

It's possible that the new MAF was not needed, but since it's the original part I don't feel bad about replacing it. I will keep the original as a spare.

What I learned... 1) You guys give good advice. 2) You can do a lot of work yourself and save a boatload of money. 3) Invest in a code reader.

All the best to you and yours...