Hi Everyone!
This is my first posting in this forum, and I just want to say how great this forum is. I am a regular reader on the benzworld W163 forums, its great too but I would like to see more how-tos, much like those found here!

I have a problem that I would like some advice on. I changed out my spark plugs using the DIYs available, and i believe I did it pretty well considering the mechanical idiot that I am. However, I have found that my 2001 ML320 is starting to shudder rather hard during idling, especially if I idle for more than a couple of minutes. This happens whether or not the engine is cold, and I have noticed that the idling rpm is hovering just around what I estimated to be 600rpm. Any ideas? I have taken out the spark plugs again to make sure that the boots are tight, and used antiseize and spark plug dielectric grease during my DIY. I am thinking that the following might need some looking at, ignition wires or, the throttle control in the engine bay (dont know what this is called in tech-speak)

Any advice or comments will be greatly appreciated!!!


***BTW Phil, I am the guy who called you last week about the brakes and rotors and I have to say that you exhibit excellent customer service to even a non-customer (you dont ship to canada). The day you do will be the day many of us canadian owners will be calling you for parts!!! Please do reconsider!!!

THE biggest problem with the wires is the excessive gap that the plugs devolop....the farther the spark has to jump the SHORTER life that the wires will have. ALSO removal of the wires is very critical..the ends "weld" themselves to the plugs requiring extreme force to remove them & that causes the wires to fail.

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hi Doc,
So in your opinion, the culprit is the ignition wire? Also, would i have to purchase the entire set of wires (12 plugs) or can I simply purchase one pc?

Thanks!

patrick

did you ever cure your misfire / rough idle ? ?
I have the same problem.

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Steve Danville
what i did myself.
CPS
rear shocks
MAS x 3.
SparkPlugs (twice)
Fuel pump & Filter
Window switch
replaced both failed horns with Honda horns.
Cleaned ERG Tube
Oil changes
Oil consumption Fix
Brake Pads
A/C Recharge
Anti-Freeze change X 2.
Front Shocks. Monroe. $90
Mercedes Warrenty Work:
Harmonic balancer,power steering clamp. Cat converters.Drive Shaft Bearing.s
Replaced Outer Lower Tie Rods and front lower ball joints at 156,000 miles

It would seem I am having a similar issue in my 2000 ML320. It starts fine but idles quite roughly when I am sitting in park, or at a stoplight. I was just recently informed that the serpentine belt tensioner needed to be replaced and I have the parts for both the belt and the tensioner. I think this problem with the idle is new. Could it be bad fuel? I guess I'm looking for the most inexpensive place to start troubleshooting. Thanks in advance guys!!!

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1993 300D 2.5 Turbo
Daily Driver.... 238,000 miles and counting (Gone for an '03 Camry)
2000 ML-320
New Daily Driver...139,xxx and still in one piece...