[sednec]

I Have1999 Ml 320 Runs Teribble, Cel Light Is On Codes I Have
P0170, P01703, P0179, P0300, P0301, P0302, P0303, P0304, P0305, P0306,
Cleared All Of Them They All Came Back After 20 Minutes Of Driving, I Know P0300s Are Miss Firing Codes, But They Can All Be Miss Firing Atsame Time, Any Suggestions?
Already Changed The Maf,
New Spark Plugs

 

[Qzyn]

Hi!!

Yr ML is almost the same model year as mine.
When purchased my ML'320 about 12 months ago I had also many "misfire" codes.
Spark plugs were first in row to be replaced with over 100k miles on the clock.

What about your spark plug cables???
I have replaced 8 yrs old OEM cables on my car with Karlyns and I'm really happy with the result.
(Only good wine (and my woman) gets better with age )
No misfire codes so far.
Next thing to look at are ignition coils.
Take a look at yr cables!!!

CU

 

[piperca]

I am experiencing a similar problem. The catalytic converters on your (and mine) year ML are suspect. There is a recall for the catalytic converter cracking at the weld, so you might want to take the vehicle to your local dealer and have them check if the recall applies to your vehicle.

I find it hard to believe that all of your ignition coils, or even your spark plugs, would fail at once. The missfire codes, coupled with the P0170/P0173, I would guess it's your cat.

Don't throw money at it without getting it diagnosed.

Please report back with the solution to the problem. I have seen too many loose ended threads on this board where people don't advise what the remedy was to their problem. There are alway others, like me, who will have similar problems and would like to know the outcome/solution.

 

[Michael Pillay]

I agree with piperca. You are getting the MAF codes and misfires on all cylinders. Could be both the cats. Just call the dealership with your VIN and ask them about open recalls.

 

[benz-tech]

bad gas, or, wires- but that ususally isn't all cylinders at once, or sensor adaptation- dealer would need to reset this after a misfire is fixed (or even motor mounts replaced bla bla) so that it bases is misfire threshold off a smooth running engine instead of one that has been misfiring for a while. even then, fuel is the most likely culprit when ALL cylinders are showing a misfire, lack of fuel can be caused by bad gas or plugged filter or pump etc.