Fluctuating idle speed
Sometimes it is steady ~700rpm and other times it varies up and down by a couple hundred rpm as if someone is playing with the throttle i.e. goes up to 800 then back down to 600 then back up to 800 and so on every couple of seconds.
2nd problem:
from idle if I increase the throttle gradually no problem, if I quickly push it down the engine stumbles and then catches up to the correct rpm
i got the same problem... i thought i might have something to do with the spark plugs not being changed for the last 80,000kms on my car.
guys, any input would be helpful.
Thanks in advance
Well I've heard that in other threads. what I've gathered is (in importance order):
-check intake filter first
-check spark plugs
-clean MAF sensor
-change fuel filter
-check for clogged catalitic converter
hope it helps.




and check the wiring harness below the cam sensors for oil (and pray that you don't have this problem) https://mbworld.org/forums/showthrea...light=campaign
Cam sensors were replaced under warranty
replaced new air filter
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Now, if your engine is runningrough as well as the idle speed v arying, then I would be more concerned.
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Seems that my 2nd problem corrected itself just out of the blue
I tried to do a search in resetting the throttle position sensor but could not find the link, if someone could tell me how it is done that would be great
if that doesn't work- check your connection between the airbox and throttle body- could be an air leak there and the engine could be pulling in unmetered air. also clean the maf with electrical contact cleaner.
To RESET the throttle Follow the following steps:
1. Turn the ignition key to the on (NOT start) position.
2. Press the gas pedal to the floor and HOLD for five seconds.
3. Turn the key to the "off" position (don't remove the key), then release the gas pedal.
4. Wait at least two minutes - don't do anything.
that should reset the throttle position sensor. Please try the above and report back.



