need help! Terrible Idle
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Joined: Jul 2007
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need help! Terrible Idle
I am having a crazy problem with my 2003 e500.
When the car is in park or any gear it will begin to shake very badly. When I start to accelerate it stops as if nothing is wrong. I am getting terrible gas mileage though. I have replaced the motor mounts so its not that. I also replaced the fuel filter/pressure regulator. Could it be the fuel pump? PLease help!!!
When the car is in park or any gear it will begin to shake very badly. When I start to accelerate it stops as if nothing is wrong. I am getting terrible gas mileage though. I have replaced the motor mounts so its not that. I also replaced the fuel filter/pressure regulator. Could it be the fuel pump? PLease help!!!
Member
Joined: May 2006
Posts: 203
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From: NEW YORK
E 63 AMG S
Most likely it is either a bad spark plug wire, a bad spark plug, bad coil, or a fuel injector. Your best bet is to have it diagnosed and see exactly what codes come up. Therefore, you will take the guess work out.
Last edited by nikon; May 2, 2008 at 09:02 PM.
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2006 CLK 350 Fog City, CA, USA
Maybe the cold start valve is bad??? Pull a few sparkplugs and take a look at the colors for correct mixture. Measure fuel pressure at idle to see if the fuel pump is working correctly. Hard to diagnosis the problem through Cyberspace! 
MBWorld Fanatic!
Joined: Mar 2006
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From: Louisiana
03 E500 and Corvette
If there are no codes I would suspect a bad plug wire as listed. The only other thing not electrical I have experienced was a stuck open egr valve.
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From: Sacramento California
2007 S550 (S65 Package)
i dont know if this is it but my cousin has a bmw and it did the same thing and it seemed to be the fan or fan clutch. like i said im just saying that it might be the fan im no expert just my 2 cents
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MBWorld Fanatic!
Joined: Mar 2006
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From: Louisiana
03 E500 and Corvette
I have had a stuck egr valve open and it was only a issue at idle. The MAF and computer system compensated by using the O2 sensor detecting lean mixture due to extra air and compensated. But this was on another brand of vehicle.
Member
Joined: May 2006
Posts: 203
Likes: 12
From: NEW YORK
E 63 AMG S
I am having a crazy problem with my 2003 e500.
When the car is in park or any gear it will begin to shake very badly. When I start to accelerate it stops as if nothing is wrong. I am getting terrible gas mileage though. I have replaced the motor mounts so its not that. I also replaced the fuel filter/pressure regulator. Could it be the fuel pump? PLease help!!!
When the car is in park or any gear it will begin to shake very badly. When I start to accelerate it stops as if nothing is wrong. I am getting terrible gas mileage though. I have replaced the motor mounts so its not that. I also replaced the fuel filter/pressure regulator. Could it be the fuel pump? PLease help!!!
Member
Joined: Apr 2008
Posts: 178
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2006 CLK 350 Fog City, CA, USA
If the MAS is going bad it will throw an ambiguous 0170 error code!!! Shaking could also be bad engine mounts but not if the fuel economy is bad!Scope the engine or pull some plugs and take a look...
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i have replaced all these items within the last two weeks
motor mounts
air filters
maf
plugs
fuel filter/regulator
The car was running amazing then one night i pushed the car a little bit accelerating quite hard.. when i got to a stop the car began to idle horribly.
I am thinking it is the fuel pump
motor mounts
air filters
maf
plugs
fuel filter/regulator
The car was running amazing then one night i pushed the car a little bit accelerating quite hard.. when i got to a stop the car began to idle horribly.
I am thinking it is the fuel pump
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Joined: Apr 2008
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2006 CLK 350 Fog City, CA, USA
OK, but you still need to pull some of the plugs and see the condition... if they are fouled, the engine will never run smooth. If all plugs are fouled, could be a leaking cold start valve.
If you can't scope the engine the you could also pull the ignition wire from one spark plug/ cylinder at a time while the engine is running and the BAD plug/coil/wire will have no effect or drop in rpm.
The other thing to check is the O2 sensor... how many miles do you have on the car? If the engine is missing badly the raw gas will kill your catalytic converter!
Like someone else said.. check the ERG valve to see if it is stuck closed.
Did we miss anything else?
If you can't scope the engine the you could also pull the ignition wire from one spark plug/ cylinder at a time while the engine is running and the BAD plug/coil/wire will have no effect or drop in rpm.
The other thing to check is the O2 sensor... how many miles do you have on the car? If the engine is missing badly the raw gas will kill your catalytic converter!
Like someone else said.. check the ERG valve to see if it is stuck closed.
Did we miss anything else?
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Joined: Apr 2008
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2006 CLK 350 Fog City, CA, USA
OH.. almost forgot... happened to my E260 once... it has a leakiy fuel distributor !!! Hopefully not, 'cuz it is Expensive... I think you take a flashlight and look down pass the Throttle body and if it is "all wet" then the FD is leaking.
