'97 c180 cutting out..

sorry 1996 not 97. hey. my mums c180 AUTO is a right sod this year. got only 64k on the clock and for the past fmonth it has been fien, BEFORE; it would cut out usually when you had the radio on and were at low speeds, usually coming to a stop. no warning, always started up again just very random engine stopping. took it to merc a few times and they said no faults at all they just reset something as you do after a head gasket job appaerntly. i have done the head gasket, then changed heads etc totally cos the cam decided to snap in half on the road test, then we have done a couple of little things to the gearbox as the vac pipe come off and the prop coupling was shot away. and replaced the battery. AND i redid some of the engine wiring loom as this car obviously still came with the crap wiring loom that falls apart after a few years. AGAIN, we have had merc and the aa etc and an auto electrics place look for a bloody fault and there is absolutely nothing to report.

NOW, after a month, it happened again today as my mum was going along without the radio on.

the only thing i will say is the car will not start after removing the battery cos i was sat there for DAYS trying to start the bloody car after changing the battery on a few occasions! it was having none of it. but out of the blue afetr a few days of struggling to start (and i even tried my new 700 amp v12's battery and got the same shitty response from the car) it was fine, and is still fine starting up. but again if i pulled out the battery it will really go bad again.

i dunno what the hell is going on. ive spent nearly a thousand pounds on this low milage poxy car and thats with me buying cheap and doing it myself! it just stops. for no reason. no warning light no noises no nothing. ecu doesnt even have a record. (oh and no i dont have a cruise control!)

any ideas?