Open to suggestions, #2 misfire
 

On our 200 ML320 with 65k miles, I got a simultaneous rough idle and check engine light. Code says 0302, misfire on #2. ( I actually looked, and the cylinders are marked 1 through 6. What a concept)

I installed new plugs, Bosch Platinum 2's, checked resistance on plug wires at 2k ohms. I then cleared codes and on restart the CEL came on, and the same codes popped right up again. I pulled off the coils for #2 and #3 and swapped them. Cleared codes, and same results.

I am looking for suggestions as to the next steps, or in their absence, a referral to a good independant shop in the Hayward/Oakland California area.

sameo sameo
 

Same exact thing here.
Ordered new STOCK Bosch plugs. replacing my 5000 mile old Bosch platinum 2's.
Are you in a cold weather state ? ( Michigan here )
Mine runs ok until its 32F then get some misfire codes. PO302 the most often. I understand there is more resistance in cold weather and the cheaper Bosch dont cut it.
I will Update tomorrow after I install the New Stock $12 a pice Spark Plugs.
2/2/7 because of the single digit tempatures we in Michigan are experiencing, I only replaced the plugs in CYL. #2. I still has a little occational stumble at idle.

I once replaced new plugs only to replace 2 new plugs in the same cylinder twice as they were faulty.

Which Cyl ?
 

It wasnt number 2 was it ?

Seems with the ML320 the PO302 is popular.
Thats my most reoccurring code.

It was on another vehicle but my point is that even expensive and inexpensive plugs fail. Also you don't know if someone dropped them - now you have a hair line crack etc.

Hey there Mr Speilberg. What happened ? Any fix ?

It has been Zero degrees F in GR Michigan so I only changed the plugs in Cyl #2.
Idle not too bad but still not a smooth idle.

For some reason, the Mass Air Flow meter will set the misfire codes. I would bet it is the culprit. I think NAPA now sells the insert for the MAF device, though you may want to buy it from a dealer to get the one year warranty.

Fall out on NEW MAF units is said to be approaching 20%

Jim in Phoenix

Jfree 20% ? Mass air flow sensor failure.
 

I would guess higher.
Where do you get your stats ? I thought the sensors wore out only a hair better then tires.

I had a similar problem with my ML at about the same mileage you had and it ended up being the ignition cables; but they aren't cheap! Just my 2 cents...

How much is the ignition cables, I have a 2001 ML320 about 61,000 miles. Just changed power steering pump, fuel pump. cost me about $1500.

I dont think I can take it anymore if I have to change any more expansive parts.

Thinking of getting a 2004 ML500 from dealer so I can get the extended warranty to cover any repairs..

check EBAY
 

Buy your stuff on line and do it your self and you would pay 25% of what you paid.
Thats what these forums are for in my book. Step by step instructions.
Next week I change the trans filter and fluid.

I am wandering if you have read the following thread. Although it might not have exactly same symptoms but very educational thread on engine misfire.

http://www.benzworld.org/forums/w163-m-class/1260892-engine-problem-asking-help.html?highlight=misfire+%232