I just purchased a 99 CLK430 and I had a pre inspection done at the MB dealer. The seller had the car worked on there when it was needed. The tech told me they recently replaced the Mass Air sensor and had the scheduled maintained done. The car ran good it seemed for a few days then I noticed a sluggish feeling when I would step on it. When I first noticed it I was starting from a very slow speed and it was having problems shifting up and later when I would punch it at higher speeds it would be very slow to pick up speed. I came on here and panicked about the tranny horror stories so I took it to the dealer and had the tranny fully serviced and there wasn't any problems with it. The next day I brought it back because I was still having the same problems. They ran some test and it showed it needed to have a adaptation reset for the new mass air sensor. They did that and it ran perfect for 4 days. Like a bat out of hell, the car hadn't ran that good since I owned it. Now tonight it came back again and when I punch it the RPM’s hang out at about 3k and it is very slow to pick up speed. I basically is falling on it’s face when you hit the gas hard.

Please help with any ideas.

 

Do 99's have the adaptive throttle? You may want to try the adaptive throttle reset.

• Turn the key to position two, but don't start it.
• Floor the throttle and hold it for 30 seconds. By floor it, I mean push it to the floor, and then press a little harder, to push the button under the throttle pedal (99's have the button, right?).
• With throttle on floor, switch the key to off, but don't remove it, then let the throttle up.
• Remove key after 2 minutes.

Some people say you don't have to leave the key in the ignition for the full two minutes. If this makes a difference, then the throttle is adjusting to your normal mode of driving.

 

I thought that was what they did at the dealership when the did the adaptation reset?? Is that not the same thing?

 

hey.. i have a 01 clk320, i have that same problem.. also... when i start my car i have to wait a while before i can drive.. also when im playing in 2nd gear and go up for 5k rpm's my car will jump, then wont let me go any higher than 3k rpm and at idle, it will shake a lot. I'm still waiting on someone to tell me whats wrong.

 

Does anyone have any ideas, I'm desperate for help. I ordered a CPS for preventative maintenance since I read so much about people being stranded, does anyone here think that could have something to do with it. The dealer mentioned that it was giving some weird readings when the car was warmed up but they didn't know if that was for sure the problem. They wanted $300 to replace it so I ordered my own and found the DIY in the forums so when it comes I will replace it hoping that it might help but after doing the homework it didn't sound like the CPS would cause this problem???? Any ideas?

 

Nope! the CPS will not help the situation. CPS is for cranking/starting problem. Yours is picking up speed (reaction issue). Do like what MarcusF said or an ECU reset. It will help but for how long? then I don't know. Yours is just getting back to the "limp" mode so quickly so there may be some other things wrong with it.

Good luck