I have a 2012 ML350 4Matic with about 51,000 miles on it. I am the second owner.

I noticed that on a warm restart there is a mild backfire, just a low poof. Doesn't do it on a cold start; and ambient temperatures have no effect, i.e., it does it on practically all warm restarts.

What's going on? I talked to the substitute service manager (scheduler); he wasn't sure.

Thanks in advance.

Tom