Ok, so I confirmed I'm running the right plug, dealer gave me part number 0041591903 which corresponds to Bosch FR8DPP33+. Sounds like the gap is 1mm, can anyone confirm?

Also have a new MAF to try as well to see if that's the culprit.

To recap, car starts/idles great. Light to moderate throttle feels good, it's when I go WOT either under power or from a stop that it stumbles from about 2800-4500 rpm, after 4500 it surges and has lots of power.

I need to pull the new plugs and apply anti-seize anyways, hence the reason for checking the gaps. Any other thoughts on the culprit would be appreciated as well, I don't know what else to check for. Car ran fine before I did the plugs/wires/fuel filter, pretty sure it's not the fuel filter, doubt it's the wires (were brand new Bosch wires, yes they're installed correctly), so that leaves the plugs, or possibly the MAF or maaaaybe the 02 sensors.

Anyways, gap confirmation would be appreciated, as well as any other thoughts on this bug.

Thanks!

plug gap should be .8mm. I doubt this is your issue. They come pregapped. Don't bother with anti-seize on the plugs.

Some possible issues could be MAF, fuel delivery, intake manifold flaps, unmetered air leaks. o2 sensors won't make that much difference in your driveability.

Having a qualified person look at your car would get it fixed and diagnosed in 1 hour or less, I'd just bite the bullet and take it somewhere that is good and be done with it. You could waste alot of money throwing parts at it in an attempt to fix.

Why no anti-seize on the plugs? The old plugs were a scary ***** to get out after 93K. Granted, I'll check them more often than the p.o., but still.

I also ordered new gaskets for the MAF, so they are going in at the same time as the replacement MAF. If the MAF doesn't fix it, it gets returned (thank you Amazon).

It's almost due for MAF/o2 sensor replacements anyways, so if either of those fixes the problem, perfect, otherwise, yeah, it's going to a shop to diagnose the issue.

Always remove and install plugs on a stone cold engine NEVER hot. You could strip the treads in the alu heads

Oh yeah, I'm aware of that DRB. Anyone recommend against or using anti seize compound on the plug threads?

You can use anti-seize if you want, it's just not needed, and it's trouble if you get any on the electrode, insulation, or ground strap. I have never had one 112/113 engine pull threads, and I've been around as long as the engines have been out. The factory doesn't use it, we never use it, WIS does not recommend it, and there has never been one single problem in my shop.

I wouldn't worry about the heat thing either, people come in off the highway and wait and will have us replace spark plugs. I know other manufacturers maybe have problems with their heads, maybe they use a different grade aluminum, I'm not sure, all I know is Mercedes.

Amazing and great information, thank you benzslo!

I never use anti-seize either and I was recommending work on a cold engine to avoid burnt fingers when fiddling around down there over the manifolds and also as space is very limited....

Benzslo, great to have you on the forum too

Well, I won't be needing to check the plugs, or gaps, or anything else. I did check one plug last night and it wasn't super tight in the hole, so I may re-torque them a bit, but the gap was fine, etc.

So, yeah, I found the culprit. It was pretty cheap, easy. Drumroll.......the MAF.

I changed that out last night (with new gaskets, if you haven't ever replaced those, I highly recommend it, one for the MAF to elbow connection, one for the elbow to intake manifold connection).

HOOOOOLLLLLLEEEEEEEEYYYYYY ISHT! I thought I knew this car was fast, but oh my gawd, I am simply blown away. The car goes like a bat out of hell, you should have seen the smile and heard the evil laugh that came outta me last night.

So, this saga is closed, yay. Now on to the other little things.

Oh, also had the car lowered on #1 pads and Euro springs, here's a pic, and had the res cut out, sounds a-mazing. Thanks everyone!

#1 pads front and rear is standard fitments for Euro suspension...

That would be why it looks so good =)