hi guys

having trouble with my 04 55 kompressor. 140k km now. simptoms are somewhat similar to others debated in other posts here but not quite the same. i took it to different garages including official benz before posting here, i will detail the symptoms and maybe one of you can shine some light pls on what is going on. i m no mechanic so apologies if some of my assumptions don t make any sense

regardless if it is a cold or warm start sometimes in the 1st few minutes or driving the engine surges or dies completely. generally when coming to a stop or going over a speedbump at low speed.. or even when turning the wheel. sometimes it will not start at al (cranks for good couple of seconds before it dies) and on the next try it starts just fine with black smoke coming out the exhaust

no error on the tester.

changed fuel pump (about 1 year ago - 20k km)
changed cps
changed plugs and made sure all connections are good
cats were clogged and rattled - did decat (am still sometimes getting o2 sensor error - check engine light - even though i put spacers on and flashed 'decat' ecu map - will put back stock ecu file after i buy new cats)
cleaned throttle body


air flow sensor delivering constant reads within normal values but i am thinking of changing it regardless
am also thinking it might be coils
could it also be injectors??

i noticed until the car warms up the abc pump makes a high buzzing note..can these get stuck and stall your accessory belt, leading to engine stop?
also when the car dies while driving, sometimes i kind of feel like there is something 'stuck' from the gearbox (similar to coming to a full stop in a manual while engaged in gear).. gearbox was showing copper filings when i changed the oil some 10k km before the engine stall symptoms appeared.. changed it again and there were no more filings. it shifts smooth and never had any issues with it.

any advice is much appreciated, thanks!

I'd check the Knock Sensor.

see > knock-sensor-symptoms

I had a similar problem with engine cutting out it was sorted with crank sensor

already changed crankshaft sensor. will look into cam and map sensors. fuel pressure sensor..knock sensor maybe??

could be anything and it s driving me nuts because aside from the occasional o2 sensor error (decat) i am not getting anything else on the star.

i will also check the tank fuel strainer and will update this thread with progress.