Whilst not strictly a doblo, its a saab 1.9tid but hopefully relevent as same engine more or less, same ecu.

Had a few problems with the engine stuttering, shutting down, coasting to a halt, but restarting ok. Codes P2150 and P2147 in Ecu, Injector low voltage on bank a and b! Recently had a new alternator.
Disconnected the electrical connector to each injector, sprayed with contact cleaner. Also followed the harness back from the injectors to a connector into the main loom (top left of engine) disconnected and again sprayed with contact cleaner (lo, connector is immediatly above alternator). So far ok, 70 miles without reocurrance and 54mpg seems up a bit although that may just be wishful thinking.

Comments or insight welcome.

Darn, engine management light on again today.
...
Disconnected again, noticed a box like red silicone sleeve around the copper connectors which almost fell out, didnt seem to want to go back in without distorting and snarling up so have left it out completely. Amazing how a bit of dodgy running can completely shake your confidence in a car.

Just to finish off this thread, I needed something reliable and couldn't spare the time to properly get this sorted. So I traded it in, shame it was a good car but spent a fortune already on dmf, clutch, alternator, cam belt.