gribble

I have a 2000 E430 with 80K miles. Normally I don't floor it but the last two times I did the throttle response off idle had a major lag. I turned off the engine after no specific time frame, "minutes", not hours I restarted and everything was back to normal. I am hesitant to use hard acceleration. By the way these two incidents were many months apart. Any ideas would be appreciated. Thanks Mark

khomer2

Throttle lag could be a number of things.
Any recent fixes, changes/service?

The simple thing to check:
- condition of your air filter - see if it is dirty or restricted at all
- next, check the operation of the MAF Sensor. While the sedan is running, disconnect the elec. connector to the MAF Sensor. Any difference in it running?
- next, jump into the sedan and drive forward from a stopped position. Any difference?

No CEL?
There could be saved codes so I would suggest you scan (borrow if need be) and post here.


EDIT: forgot to ask
with the MAF connected....
When you start the sedan cold and immediately take off, describe the problem, if any.

When the motor is fully warmed up, what's idle speed?
At idle speed, is there any shaking or rough running of the motor?

gribble

Khomer 2 thanks for the input. The car runs as normal, idle,acceleration, smoothness all normal. No actions have been performed on the car prior to these ocurrences. I think that the throttle by wire comes out of calibration when I jump on it and then resets when I turn it off and on. It is the perfect car until I accelerate hard. Thanks again Khomer 2, Mark

loden338

Try resetting the transmission.
https://www.mercedesmedic.com/reset-...-instructions/

gribble

The transmission shifts normally and smoothly. In case I did not mention it the car is fine now. I am just hoping someone might have a clue about my occasional problem which causes me refrain from rapid acceleration.

khomer2

Have to run the first basic checks above as suggested?
And the results..?

You still need to perform a scan to see if there are any saved codes. It may not show any CEL or codes as they could still be pending.
Do fool yourself thinking this is an occasional problem.

fabbrisd1

Please follow the instruction for "tranny TCU reset" - over time the factory default tranny settings to "less progressive" shifting - also called "adaptation" a quick reset about every 6 months - which just takes 2-3 minutes - restores the correct settings - free !

christoh

99% sure it's your throttle position sensor. I had the same issue with my 2001 W210 E55, it would drive fine, no issues, I could accelerate normally but once I pushed it past kick down (ie, to the floor) it would be like a snail in molasses and the CEL would appear. Turning off the car and turning it back on resulted in it being all good again until I pushed it past kick down, and once again it would crawl. I solved this issue by installing a new throttle position sensor, now I can overtake no issues.

- Chris

gribble

Thanks Christoh, I am in the middle of checking suggestions from Khomer 2, so far nothing. I just checked on a replacement TPS about $150. What you stated sounds just like my problem. I am going to drive and recreate the problem and see if the CEL comes on. Does yours turn off after you do the reset by turning the car on and off? Mark

gribble

Khomer2 air filter- good.
engine smooth cold and warm.
idle warm 700 RPM
I did not do the MAF test yet, I was wondering if disconnecting would cause a CEL? I will get a scanner for stored codes, no CEL now

gribble

Well I took the car out and tromped on it four different times from different speeds and every thing is OK for now. My favorite, problems are the intermittent ones, ha ha. I will still scan for DTCs. Thanks everyone. Mark

gribble

Just read my original post, what I should of said is the throttle lag does not occur until after stomping on the gas. Sorry

christoh

You're describing exactly what happened with my car. It drove fine until I floored it past kickdown and then it went into limp home mode and the CEL came on. Switching off the car and switching it back on cleared the issue and the CEL, until I once again floored it past kickdown. It was the throttle position sensor, cheap and easy to replace.

- Chris

gribble

I replaced the throttle position sensor and all is well

christoh

Glad to hear your issue was sorted.

- Chris