bud1326

My 2002 S 430 has a problem with hesitation when starting up from stop signs, red lights, etc. Tach shows rpm dropping to just about 1000, and when you press the throttle a couple of times, it finally takes off. Once you are over 40 MPH, it runs fine. The gas pedal was replaced with a new one. The Mass air sensor was cleaned two times, and still no change. I had the independant garage we have always used, clean the throttle body and injectors and both air filters were changed. I never get any fault notice or error codes shown. My mechanic is stumped. The nearest MB Dealer is 150 miles from where I live.
Does anyone have any ideas of what to check next? We talked about replacing the MAF with a new one, but I hate to spend that much $ and find out that was not the fault.
So if anyone of you can point us in the right direction, we would appreciate your help greatly.

Jack_88

I'd be inclined to check the fuel pressure, see if you have an issue with the pump or filter, but that's just a wild guess.

bud1326

That is now added the list. Wild guesses are what we are looking at now. Anything is worth a try.
Thank you Jack

blackopal

I too like the idea of a bad fuel filter, especially if it hasn't been done in some time.


If you hadn't said you changed the gas pedal then that would have been my first guess.


The symptoms you describe were very much like the ones I had and mine turned out to be a bad pedal (which I replaced with a genuine item).


I knew it was my pedal as the car was rock solid when accelerating using the cruise lever only. Can't remember how slow you can go and still accelerate with just the cruise but it may help you rule out your replaced gas pedal?

bud1326

I am going to replace the fuel filter now. They should have done it when they were doing the MAF throttle body and injectors yesterday. Hope i can find one locally.
Thanks for your input

Bud

tusabes

Was the gas pedal a new mb part or bought used or on eBay listed as new ?
Many defective pedals are sold on eBay as new

bud1326

It was a new MB part from Parts Geek, they said. Although the pedal had a kickdown switch, that did not have a plug in for the 2 conductor wire, like the old one. So I popped the old one out and snapped the old switch in it's place and the kickdown did work ok at speed. But it did not cure the problem I had with the hesitation etc. So, I now have a new fuel filter and I could not get the car high enough to get the cover off in front of the LR wheel. So I am going in to the Garage in the morning and let them install it. I just hope it takes care of my problem

Thanks,
Bud

tusabes

Maybe it's your old wire /switch that's bad , and you are re using it ?

bud1326

I don't think that switch is even in use until you floor it to drop down a gear. I can drive 50, kick it down to the floor and it will drop down to 4th to pass. That is working OK.
So I think it has to be something else. The guy I bought the car from, said he replaced the pedal 2 years ago and then had no problems. So that is why I replaced the pedal this time.
But that did not cure it so now I will try the fuel filter. After that, if it still acts up, I don't know which way to go. Some other poster on this forum said the auto transmission conductor plate would cause this problem if transmission fluid leaked past an O ring seal on the wires going into the tranny. That's way above my pay grade, so my last resort is to take it to the nearest MB shop and hand them my wallet and deed to my house and tell them to fix it. I hate when that happens