My 760 (B230FT) wagon has been giving me VERY intermittent fits of power loss for about 2 years. I made some posts on this site and everyone said to start with the basics. Well, the problem appeared to be HEAT sensitive in the engine copmpartment. This turned out to be a false positive.

After replacing Ignition coil, ignition wires, spark plugs (one was cross threaded by the dealer), air filter (old one had seal damage, can only imagine what that did to the AMM), Fuel Pressure regulator, Ignition Power Stage (yeah, that little electronic device about 10mm from the negative battery post), Voltage Regulator, Radio Interference relay (Fuel Injector relay), distributor cap and rotor, cleaned throttle body, and had the timing checked.

It got worse. Poor starting - starts great, then dies. Turned out the throttle body (not cleaned by me) was never removed to be cleaned! WHile driving the RPM's would jump around from 800 to 2000 - the ECU was trying to keep the engine alive - pushing the accelerator made it worse! The original symptoms was loss of power at 3500RPM but letting up on the gas would recover without stall. This behavior became very much worse and worse as the months and lately days grew longer.

Problem: Fuel Pump relay has two windings - one of the windings had a broken strand! I was losing fuel pressure from additional heat in the center console behind the radio with all the other relays.

Side note: My headlights had been acting up - both would go out. Relay related because a good whap on the center console fixed the lights. Must not have helped the Fuel pump relay!

Lesson: I bought the "Bosch Fuel Injection & Engine Management" book by Probst from amazon.com. I've read the first two chapters and would have zeroed in on that relay in a heart beat had I known it existed. I knew the whole time that I had an electrical problem - not mechanical. I just didn't know how the system was designed to work and all the parts involved with Engine Management. Strongly recommended for reading before trying to diagnose intermittent problems.

Also, I had read all the FAQ's and Performance Tuning sections on Brickboard.com which did make sense, but none of them ever mentioned this problem - the fuel pump relay having a broken winding. Uhg!

The great news is this machine runs so well that I left an impression in the driver's seat during a harsh test drive! It's a dream to drive and it purring like a kitten.