tali1

I was driving my ml and I was at a red light and as soon as the light turned green I tried to accelerate but the Ml began to buck and the ML wouldn't accelerate over 30mph. The check engine light was also flashing while driving. I ran the codes and it was a cylinder misfire on cylinder 6 and 2, aswell as a o2 sensor fault.Is it normal for a misfire to occur suddenly?

Maj. Dundee

Of course it's normal, just like every other problem in life.

Whenever the CEL is flashing it is telling you that the misfires can damage the catalytic converters (TWC).

Check the spark plugs and ignition wires.

tali1

Hi, I swapped out the coils and plugs and the misfire issue is gone, however I noticed that when the vehicle is in park the engine revs to 2500 rpm no problem but when I put the Ml in drive and attempt to give it the slightest gas the vehicle still bucks and the pedal feels totally unresponsive. However once the Ml builds speed with about 10% gas it shifts fine and drives alright until I press down the gas pedal further and this is when the motor feels like it's breaking up. The codes that came up in the scanner were P0170 (Fuel Trim Malfunction Bank 1) and P0173 (Fuel Trim Malfunction Bank 2). Any ideas?

Maj. Dundee

What do you mean by "swapped out the coils and plugs"? Did you buy 8 new coils?

tali1

HI, sorry I wasn’t clear I replaced all the coils and all 16 plugs. I thought I had a problem with the maf so I unplugged the battery for the night and I reconnected the terminal. I tried to start the ml and it ran then died I have fuel pressure but the ml now just starts then dies. I ordered a new oem maf once it arrives I’ll reinstall the maf and update you on if the issue is fixed thanks 👍

Maj. Dundee

My suggestion was that you check the plugs and wires, not the coils. It's rare that coils are faulty. Where did you get the idea to change all of the coils?

OE coils are $205 apiece. And I hope you didn't throw them away because there is nothing wrong with them.

Why you want to change the MAF is a mystery. If it was faulty, there would be a code for it.

You came to the forum to ask for help and you have ignored suggestions and you are just guessing at things.

tali1

Um absolutely not sir, I took your suggestion serious and I was coming close to replacing the coils and plugs anyways its been over (60,000miles) so I decided to replace everything, I got a good deal online from a gentleman than never installed the oem coils or plugs on his ml. And no worries I keep all my parts I replace. And for the MAF I read in another MB forum that the issue can pertain to a dirty MAF so why not its very easy to check and insure. Thanks for the replies and suggestions. The Ml doesn't misfire anymore but I don't have throttle response when In drive, Im gonna take the Ml in to my local MB shop. I'll let you know what the verdict is.

http://www.benzworld.org/forums/w163...170-p0173.html

Maj. Dundee

Try this procedure highlighted in green.