Car reving itself in park.
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Newbie
Joined: Apr 2023
Posts: 3
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GL450
Car reving itself in park.
I have a 2009 GL 450 (X164) automatic and have been having some problems with RPM's rising up to 2000 while in park and stays there for a while. You can bring down the rpms by pressing the accelerator, but after some time it will still want to rise into the 20's. Been to many garages, many things have been replaced like spark plugs, ignition coils, but it's still acting up. The car has been diagnosed a few times without any success of finding the cause. Starting to lose hope here my recent thoughts would be that it could be the idle control valve? Also should mention that the car can sometimes stutters while driving and pressing the accelerator fixes that.
No clue where to go from here, maybe someone has dealt with this, because I'm running out of garages arround my town.
No clue where to go from here, maybe someone has dealt with this, because I'm running out of garages arround my town.
Out Of Control!!
Joined: Apr 2019
Posts: 11,924
Likes: 6,776
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
I have a 2009 GL 450 (X164) automatic and have been having some problems with RPM's rising up to 2000 while in park and stays there for a while. You can bring down the rpms by pressing the accelerator, but after some time it will still want to rise into the 20's. Been to many garages, many things have been replaced like spark plugs, ignition coils, but it's still acting up. The car has been diagnosed a few times without any success of finding the cause. Starting to lose hope here my recent thoughts would be that it could be the idle control valve? Also should mention that the car can sometimes stutters while driving and pressing the accelerator fixes that.
No clue where to go from here, maybe someone has dealt with this, because I'm running out of garages arround my town.
No clue where to go from here, maybe someone has dealt with this, because I'm running out of garages arround my town.
I am thinking about... :
- loose camshaft rear plug covers or
- a bad PCV valve or
- a dirty MAF issue
- intake plenum seals
- Compromised vacuum hose
1-- Scan you car and hope to find related faults.
2-- Next look at fuel trims to find them largely positive, an indication of bypass air.
🤞
Last edited by CaliBenzDriver; Apr 30, 2023 at 10:40 AM.
