Guys I have a 1998 C-230 with about 140k miles. I am currently experience a problem where the car has does not shift properly.

For example....if I am cruising along at about 40 mph and need to speed up, I will "floor it" where I would anticipate the car to downshift to speed up. However when I do this, the rpm's go up but the car does not down shift, rather it jerks and gets "stuck" to the point it slows down to almost stalling. As I ease of the accelerator, the car finally downshifts but at this point its to pick up speed that I lost during transition phase. Any ideas? Nothing is coming up when the codes are pulled.

I have also noticed that when I drive the car from a cold start the samething happens from 1st to 2nd if I am little aggressive with the accelerator.

Any help or input would be really appreciated. Thanks

 

How old is your MAF? Have you tried spraying it with the CRC MAF cleaner that you can buy at Pep Boys? Sometimes this will help for just a short time while other times it can last quite a while.

 

I did spray it with CRC but I am starting to lean towards the idea that it may need to be replaced. Any idea on the cost? Should I buy online or through the dealer?

 

Buy it online. Much cheaper. It will take you 20 minutes to swap out using a phillps screw driver. Do a search and you will find tutorials. Autohausaz.com, buymbparts.com, etc., etc.

 

Try unplugging your MAF Sensor to see if this makes a difference, If there is an improvement then suspect the MAF. Also Try and get the ECU Codes read as this will point you in the right direction.

Hope this helps..........

 

Can this be done or will the car throw a bunch of codes?

 

If your MAF is not working properly then the Auto Box won't know what to do and when to do it, IE it won't know when to change up or down because there is no stable speed reference from the ECU.
Yes by disconnecting the MAF you are actually putting a fault on the car, but there will be a noticable difference in running if the MAF is faulty.

You can get the codes read before disconnecting it!

 

Thanks. Appreciate the information. Any idea on where I can pick up a code reader? I have a Peake Code Reader for my M5 but they do not make one for Mercedes.

 

Here in the UK thats a Dealer or Independant Specialist Job who have the Code reading setup or Mercedes "Star" Computer System.

Someone on here must be able to advise you of a U.S. alternative!

Hope you get on OK.

 

Try "Autozone" if there is one in your location.

Google Search for "Autozone Free Code Reading"

Might point you in the right direction.

Hope this helps.............

 

I was just at Autozone. We discovered that the port for the Code Reader is not under the driver side dash but in the engine compartment. Is this true?

 

So I pulled the codes again today and P0170 is the code that came up. I starting to think the following could be the problems in order:

1. Fuel Filter
2. Bad MAF
3. Intake Manifold leak

Any suggestions?

 

on a cold start the car always whines and sounds/ feels jerky. thats normal. if i remember correctly its something with the engine but its normal. my dad works at mercedes and i had asked him, my car is jerky when i first start it. he asked if it was cold when i felt that and i asid yeah. he said no worries, its normal

 

Could also be a coil pack going bad giving the Lean code.. Try cleaning the MAF first..

 

Changed the MAF and it was an instant difference in performance. Most of the symptoms are gone. I will drive it for a few more days before posting the final results. But so far so good! Thanks for the information/help guys.

 

>>I will drive it for a few more days before posting the final results.<<

Good thought. The ECU probably needs some time to self adapt if you don't do a reset manually via the key sequence (search for it) or disconnect the battery (don't forget to resync the windows, sunroof and have your radio code).

 

So the wife has had the car for a few days no and zero complaints. Seems like the MAF was the problem. Thanks to all the board members for there help. As well thanks for the link to http://www.autohausaz.com/. They have got to be the cheapest when it comes to parts and first class customer service.

 

your local auto parts will lend it to you,