Hello I'm Sebastian from Mississippi..I recently purchased a 2000 clk320 off of Facebook and got a killer deal..anyways it didn't run when I got it but I knew right away what the problem was because it had sat up in a garage since 2015..I got it home ordered a fuel pump and it ran like a dream..so about 2 weeks later I let a female friend of mine take it to take another female home..like a 10 minute there and back...that didn't happen she never came back and 3 days later got the car back with no cats from the manifold to silencer..so I got everything to fix if new cats.new O2 sensors. Oh I didn't mention that I drove it from where it was although loud it crunk and ran fine until I parked it where it is now..so when I get all the parts on it will crank and spit and sputter and sometimes will run(like crap)..I got a scanner and it was tps code so I cleaned the throttle body ordered new tps and put it on today and tho the code is gone it made no difference..I've changed the tps..fuel pump..fuel filter..checked everything and can not figure it out...I will post video of what it does later when it cools down...hopefully somebody will know what's up with it and I can have my car back...

 

Sounds like you put your trust in the wrong people; doesn't sound like a friend, sounds like a lady you wanted to impress. Gonna be honest, from the most expensive car to a hoopty, I've never let anyone drive my car. I recommend some discretion in the future regarding lending cars.

So to review, if I am correct in reading your post; you have replaced the fuel pump and filter, catalytic converters, O2 sensors, cleaned throttle body, new TPS. Assuming everything was installed properly and nothing damaged in the process, I would recommend doing a Throttle reset. Lots of videos of people doing it, I'm sure you can find them. I'll link a video below. In lieu of that, did you change the oil, check your spark plugs, check air filter? Make sure you smell the oil for impurities (sounds stupid, but seriously.) Do you smell gas, or smell coolant in the oil? Is the oil gritty or black? If you haven't changed it I would recommend sending a sample of your oil off to Blackstone labs; they'll send you an analysis of the oil, which will indicate generally the health of your engine. Too many of this metal or that metal could mean engine wear, this chemical or that could indicate this or that, or your oil could end up showing averages and the engine be healthy. Costs $50 i think. https://www.blackstone-labs.com/

If it's still running rough after doing mechanical due diligence and everything looking like it's fine, I would recommend either A) buying a diagnostic tool in order to determine what cylinders, if any, are misfiring and find in the data why. OR B) Take it to a dealer or European specialty shop. I've had friends get a car running fine, only to run awful days later for no apparent reason. It could be that there were underlying issues when you got the vehicle; it just happened to run fine for a bit because it hasn't run at all for a while. So now would be the time to really find out if there's some internal issue with the engine that can't be found by other means except either the oil analysis or tearing the engine apart. Best of luck to you here, can't wait to see the video of it running.

 

Ok here is the video guys..when I went and picked the car up it cranked and ran fine was just loud AF because had no exhaust at all..I drove it to where it's parked now..if it was something catastrophic I wouldn't put the money I've put into it to fix it..it ran just like normal for 4 miles and I shut off and didn't try to start it again until I atleast got the cats back on so it wouldn't cause further damages..only problem I had was the fuel pump when I got it..you name it I have checked or replaced it..I have mecedes scanner..not a star scanner but a decent one..no fault codes..Show quoted texthttps://youtu.be/dm1oOhgK1Dk

 

I'm assuming you meant to link this video ---> www.youtube.com/watch?v=dm1oOhgK1Dk

No lie, that sounds awful. Obviously it wasn't catastrophic or it wouldn't start or run at all. But clearly if you have checked and replaced everything there is then it wouldn't run like this. Don't mean to be rude but it's silly to come onto a forum and ask for help and turn around and say you've checked everything. You either got it or you don't man.
My best guess is this is a fuel issue still. Check the fuel pressure in every area you can -- check your injectors for gunk or buildup. Check all your fuses.
Also check IAC (Idle Air Control) Valve and/or your throttle body again. Also check the MAF sensor and MAP if you have one. Check for vacuum leaks -- could be the engine is getting too much air, causing a lean condition.

Aside from that I have no further advice except bring it to a dealership. I'd normally say bring it to a mechanic you trust but if girls are running off with your cattys then I'd start re thinking who you hand this car off to. Best of luck to you.

Also, not important, I noticed you mentioned in the video you got a brand new mercedes battery... Everstart is a Wal-Mart Brand battery. But hey as long as the CCA's and group size are a match, then whatever.