2003 CL55. Getting those two codes plus random misfires on most cyls. Never seen the 1999 before. Some that say its a "load limit is active". Happens when you are about 25% or more throttle, especially if the throttle is opened quickly. Car then hits a wall, no power, misfires badly. Shut the car off and restart all is well. Until you dip into the throttle.
Cruises fine, no issues. Just did a road trip, 400 miles, cruise set at 75 no problems.
Shifts fine.
New plugs, wires, coils, 02's, IAT sensor last summer. Worked great.
Cleared codes, thats not the cure.
Idles fine. part throttle is fine. Seems like when the supercharger kicks in is when it happens but can't be sure if thats the only time.
Has a Eurocharge tune, smaller pulley, belt wrap kit, headersm split cooling, the usual tricks.

Any ideas where to start ?

Crank position sensor maybe? Does it have the same issue when you rev in neutral? Does it misfire if you slowly accelerate in one gear to 5k rpm? Random misfire is odd.

Actually, sounds kind of like a fueling issue, running an engine lean causes predetonation (misfire). Your engine is getting enough fuel until you try to rip on it. Fuel filter? Fuel pump?

IIRC the s/c kicks on at a specific RPM if your throttle doesn't pass the required threshold. Might see if the issue is dependent on the supercharger engaging.

have fun

The weird part is that is not all the time. Just has it out, now the only codes are multiple misfires. Did a few idle to redline pulls, 1-3 gear all was good. 2nnd and 3rd gear stomp the pedal downshift pulls. Stopped the car. No codes. Did that a few times. Then on the next run it falls on its face with the codes and barely runs or idles. Misfires. Shut off the car. Restart all is good. Clear codes. Try again. Then under mid throttle but enough to engage the s/c it stumbles again. Repeat. Then it will do 3 or 4 flawless runs to redline.
CPS could be the culprit but would that not throw another code ?
The fuel filters only have a few thousand km. In my experience, starving for fuel is not intermittent like this. Once the filters are clogged or the pump is bad you don't get full power anymore. Most likely limp mode but not a misfire ? I think the it would have a code for low fuel pressure if that was the issue ?

Maybe one of the new coils / wires / plugs has gone bad. Parts these days you never know the quality even though they were OEM spec.

New parts aren't the best, true. I'd guess it's a wiring/hardware issue if it just started out of the blue.

My 55 had some odd corrosion on fuse blades and other places, might check any of those that feed fuel/spark/ecu? IIRC last time I had the cover off to replace the fuel filter, I thought the pump wiring looked kind of crappy.

Do cross forum research on other cars with the m113k- e55, s55, sl55.

Last time I got a weird code like that, there was ZERO chatter about it anywhere except for the mercedes wiki page, which was unhelpful.

Someone in another thread had that code with a bad MAF, I see...

Wonder if the TCU can trigger that code, since I know it can command the ECU to pull engine power while it shifts gears. Probably not the issue, but there's a 50/50 chance your TCU is full of ATF (it wicks up the wires from the transmission)

good luck!

If I get real tired of googling, I just buy used parts off ebay to test with.