PeachParts Mercedes-Benz Forum - 94 C280 Runs rough in cold weather

'94 C280 with 250K miles... 2 month ago I experience an uncommanded engine shutdown... engine would crank but fail to fire... searched this form and replaced the following... fuel pump relay... OVP relay... and finally the fuel filter and fuel pump... no luck until 2 weeks ago when the weather temp reached 50 degrees... engine started running very rough for 10 mins before smoothing somewhat (engine will rev smoothly to 4k then miss?)..the car is now drivable (with rough running and sluggish shifts) unless the outside temp drops below 30 degrees, car then will only limp along... just cleared p0300, 304, 305, and 306 missfire codes today for the first time since engine restarted... any thoughts???