89 300SE Starts and Stalls

My problem sounds similar to the 300CE, except that this MB starts and runs for 5 seconds and then dies. It starts again, and dies again, etc.

I do not have a fuel pressure gauge, but there is strong pressure on the inlet side to the fuel distributor. Curiously, if I loosen the return line and let it leak fuel, the engine runs, but will not idle.

Does this sound like a low fuel pressure problem, a clogged injector allowing the pressure to leak down, or "something" causing the fuel to shut off???

All comments greatly appreciated.

GB