DENNIStheMENACE

Lately I noticed that at stoplights my 320 has a very rough idle and I read somewhere that this can be caused by leaks in the intake manifold so that the ecu compensates by adding more fuel to the air mixture. Is this the problem or is it something else? Any help would be apprectiated.

MarcusF

It "could" be a vacuum leak, but if so, it would be the first one I've heard of in a CLK. Rough idling is common in CLKs when the motor mounts need replacing. The motor mounts in these cars are liquid filled. Over time they leak and the result is the engine vibrations get transferred to the chassis. Motor mounts are regular wear items.

You may wish to check the transmission mount as well.

Amir_AMG

to check if it is motor mounts, have someone rev the engine while hold the brake lightly, if there is any movement in the engine bay, it is motor mounts...you should change the transmission mount as well when u do both motor mounts...I payed 350$ for parts and labor from a friend. You can get them on ebay for 112$ a pair, but i got them from dealer.

DropTop208

It could be the motor mounts, the transmission mount, or it could also be a dirty MAF sensor.

Silverbillet

I had slight rough idling and after I changed out my plugs and wires, it was gone.

DENNIStheMENACE

I just cleaned my MAF and my idle is completely smooth. Thanks ALOT. Kinda feels wierd now sitting in the driver seat without any rumbling lol

SETSEROCK

how do you clean the MAF? i think i need to as well. the idling is rough in my car as well. im about the change plugs as soon as i find out what some good plugs are. but cleaning the MAF seams like a good idea too.

jtbeche

Used the search function. Put in clean maf. Got this post called "Instructional: 430CLK - How to change air filter and clean MAF".

https://mbworld.org/forums/clk-class-w208/189777-instructional-430clk-how-change-air-filter-clean-maf.html

Edit: I see now you have a 320, so I guess that changes things a little, but I'm sure you can use the same basic principles.

DENNIStheMENACE

On the 320 you just disconnect the airbox from the intake tubing. Right behind the tube for the air box should be a another separate housing for your MAF you'll see that under it there are wires that go into your engine. Unclick the wires and undo the metal bracket behind the housing holding it to the other part of the intake. That should free your MAF housing, the MAF sensor should be inside the cylinder shaped housing. Looking at the side where the 2 wires came out of the housing, should be 2 screws holding the MAF into the housing. Once you unscrew those your MAF should be able to wiggle free. Be very careful if you mess up your sensor itll run you 350 from the dealer. Make sure you spray it with electronic cleaner, preferably CRC MAF Sensor cleaner and make sure it says "leaves no residue". Spray it a couple times and let it airdry for like 2 minutes.

Personally I did it and it didn't completely get rid of the harsh idling (after cleaning then driving for awhile) so you might want to check your engine mounts as well thats usually due to just wear and tear. good luck