Gstone70

Ive got a 2000 C230k that we are working on at our shop. This car has had the kitchen sink thrown at it before it came to us. The issue is the car will rev at light throttle to just above 2k rpms, it then sounds like something is interrupting the ignition and it misfires, back fires through intake and will not rev above 2k. We have unplugged, replaced, inspected wiring on MAF. Replaced crank sensor, throttle valve, supercharger,K40, unlocked and replaced with used ECM, replaced coils, plugs, wires, removed valve cover and checked cam timing, tested cam advance solenoid , tested for vacuum leaks, etc. The only things that haven't been replaced that may still have something to do with this issue is the knock sensor and cam sensor. We have SDS and everything is in spec at idle and don't see anything that would cause this , it's also not throwing or storing any codes when it does this . We have done every adaptation by SDS in the engine and trans menus. We removed the exhaust to confirm there wasn't a clogged catalyst issue. I'm lost, I've searched and seen where several owners with R170s (that share the same engine) have had the same issue, but never seen where it was resolved. Any help or ideas are welcome. Thanks
Also....sometimes the car is difficult to start and will backfire through intake at times. We've check fuel pressure with a gauge while running. When the car does starts it idles perfectly , no misfires, no smoke, no issues until revving above 2k rpms.

C230 Sport Coup

I had something like this recently, but doubt it's the same, you certainly ran it without the belts to test it yes?
My alternator seized and prevented the engine from revving. Made a horrible noise too.
Had it to get it towed from the street to my driveway, but then removed belt and it ran fine.
I was glad to know it wasn't major engine damage.