2001 c180 w203

Hi I'm kizza from Canberra and I finally bought the car I've wanted since 20yo a 2001 c180 coupe pretty sure it's a w203, it's not supercharged or my dream amg but it is the shape I love in mint condition, black leather ect, the water pump failed so I left it at a mates place and someone stole...

My 2001 C180 W203 dies down after 2-3 hour drives. It's as if there were no fuel or oxygen to feed the engine. Mechanics say it's dirty fuel or the gas pump, however, fixing it doesn't seem to help the case. It keeps happening. The car is usually used for short trips, but every year or so...