Vacuum pump

No hose near MAF
Hello everyone, I'm the owner of a 03 W211 E200 and idk how many previous owners it has but I got the car in this state:

Current mileage: 201 336kms
Service history: unavailable
Running state: Yes
Driveability: undrivable
Issues: Erratic idle, Rich condition, misfiring on cylinder 1,4 and currently changed to 3,4, car struggles to move and has great lack of power.
Servicing done since new owner(me):

New:
Camshaft gears,
Camshaft magnets,
VVT Valves,
Timing chain,
Chain tensioner,
Top and left timing guides,
Thermostat,
Idler pulley,
B1S1, B1S2 oxygen sensors,
Valve cover gaskets,
Breather hose and check valve,
Injector O rings and filters,
Oil and filter,
Battery,
Intake manifold gaskets

Previous owner supposedly changed:
MAF sensor (HELLA)
1 ignition coil (FREY)
Spark plugs

When I bought the car I thought all it needed was a timing chain kit but little did I know I was in for a full servicing overhaul. I work on it myself and have changed the timing chain and related parts like mentioned above and the car was still misfiring on cylinder 1 and 4 and sometimes it's 4 only.
I cleaned all connectors, camshaft plugs had oil on it. Changed the magnets and cleaned the connectors and it fixed a previous issues related to open circuit camshaft actuator. Next is oxygen sensors, both had oil in the connectors. Cleaned and put in new ones although I believe the old ones were fine because the readings are still the same. I really hoped it would fix my erratic idle but the car is still the same.

Next I changed the crankcase breather hose and the car is still the same again. While doing so I cleaned the injectors and replaced the o rings and filters. The car is still shaking a lot and misfiring. It sounds really bad like an old car (yes ik it's old but sounds like a diesel or truck). Revving the car would smooth things out a lil but it's still bad. I did throttle calibration and idle adaptation and also cleaned the throttle body before but still nothing. The supercharger boost valve was shiny looking super clean. I've noticed that the car takes 12mins for idle adaptation to kick in where the sound and shaking vibrations will change but all problems remain.

Next problem that I noticed is that behind the engine there's a vacuum pump and there's a broken connector to it. It doesn't have any hose. Blocking it seemed to improve idle and revs but the problems eventually come back, not sure if it's placebo or the car readapts to it because on next start up all problems are here again.

I can't seem to find info on where this hose is supposed to connect because this engine fits in various cars and most info online is about w203. Please note that my car has the SBC System and no brake booster. People have showed me pics where the hose splits into 2 and connects to the brake booster and front of the intake which is right after the throttle body. Some have only 1 hose which connects behind the MAF but I don't seem to have the connection. There are no hose dangling or anything that's just how I got the car.

Live data during idle is as follows
Engine coolant temp 102c
Short term fuel trim Bank 1 0.0%
Long term fuel trim Bank 1 20.3%
Intake manifold Absolute Pressure 55.00kpa
Air Flow Rate from MAF sensor 4.80g/s
Equivalence ratio Lambda B1S1 1.150
Oxygen sensor voltage B1S1 1.869v

Live data during 2k revs is as follows
Engine coolant temp 101c
Short term fuel trim Bank 1 0.0%
Long term fuel trim Bank 1 20.3%
Intake manifold Absolute Pressure 45.00kpa
Air Flow Rate from MAF sensor 10.36g/s
Equivalence ratio Lambda B1S1 0.924
Oxygen sensor voltage B1S1 1.235v.

I see someone actually fiddled with the MAF wiring and when I touched it I got a new code now saying Intake Air Temperature circuit High input. P0113. This code wasn't there until I removed the insulating tape and saw twisted wires. I might have to redo this part but this happened only when I touched the wires. I checked voltage and it's 12.2v with the car off and 12.4 volt with the car on and I didn't check the signal voltage because only the 12v and ground wire was exposed and I see the connector has 4 wires in total.

Long story short the car shakes a lot and misfires. Revving MIGHT improve it but it's not always the case as sometimes it lags and u can feel the misfire but sometimes when I feel like there's only 1 misfire or it gets removed then the acceleration feels much better but these tests were done on neutral.
I took the car for a drive and it struggles to move with it barely going on a slight uphill road on 1st to the point I had to stop and ride the clutch because it then wouldn't move at all. At red lights I have to drive it like a loaded truck or else it's gonna stall.

Codes: P0303, P0304, P0113
All oil residue in coils and plugs removed.
Removing the oil cap while engine is running does nothing and u can feel air coming out. Swapped coils and plugs and it was still the same. Misfires were on 1,4 until the MAF problem then it seem to have changed to 3,4 but before that it was always 1,4.
Engine starts alright on cold then shakes after like 30secs.

Any help would be much appreciated. In a few weeks time it's gonna be a year since I bought it and I've done nothing but put money in it. I only drove the car like 3 times and never got to experience smooth Mercedes engine at all. Thanks a lot for reading I'll attach a few pics if I can

 

Ok, lets hope we can add enjoyment to your ownership.
I read the account of your troubles... it's not "cylinder damage" then it will be all right soon.


You are experiencing lean misfires with rich trims, right?
Pls read your fuel pressure to confirm it's down.