Hi, we own an ML270 CDI yr 2004. We started having problems (difficulty to start & then stalling while decelerating). Once, after stopping for a break on a long journey, it took 20 mins to start. We then took it to a Mercedes Benz dealer for servicing & to review the problem. It came up with fuel injector faults (? Not sure of actual codes) & they changed relays around to attempt to fix. The next day, after driving home it stopped in mid-drive, at 60kms/hr & would not restart and has not since. Mercedes then diagnosed it as an air leak between the intake manifold & engine block and $5000 to fix. We did not go ahead. We have since (at home) taken the engine apart & replaced the gaskets on the intake manifold, but it has still not started. Further, he has: a fuel leak-off test on the injectors; the high-pressure fuel pump & the fuel pressure regulator. The regulator & injectors gave minimal returns, but the hug-pressure return line delivered 60ml of diesel over 60secs. Does anyone know if the internal engine computer detects a fault, does it bypass the fuel pump - is that normal operation? Or do you think there is a problem with the high-pressure pump? We would appreciate any advice please.