A couple of times a few months ago my ML was running very rough(eng Miss) and all you would have to do is shut it off and restart and no problem for another few weeks. Eventually it set the ck eng light and threw codes P0300 and a couple of other cyl misfire codes . So at this point I changed all the very expensive plugs at only 54k miles, cleaned all the connectors for the coils and the grounds for the coils. some stuff looked like white corrosion may have been on it. ran good till today.
It threw codes P0300,P0301 and P0305 cel light on ,shut it off restarted,and the shaking stopped cel remained . Cleared the codes .Do these V6 eng cars have a common problem I should be looking at this point?

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88 W124 3.0
96 R129 119eng
06 ML350
98 ML320 sold
02 CLK55 amg

Ignition coil failure is common, spark plugs at every 5 years OR 80K miles.
Whichever comes first. Sounds like you only made the 5 years, and it came first!

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MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
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44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

Swap the #1 and #5 coils to known-good cylinders and clear the codes. The next time the mis-fire(s) occur, see if they've moved to those cylinders or remain at 1 and 5.

Thanx for the help. I will try the coil swap 1&5 to other positions.I will get back to you all in a couple of weeks when it acts up again. If it throws codes!

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88 W124 3.0
96 R129 119eng
06 ML350
98 ML320 sold
02 CLK55 amg