I've been helping a friend troubleshoot his '87 740 wagon and have had little success. It's a standard US-spec '87 740 with the B230F (non-turbo) and LH-2.2 Fuel Injection.

The engine runs great, but the fuel mixture leans out above 1/2 throttle for some unknown reason. We've changed/swapped/replaced the following components so far and have received little or no improvement:
Fuel Filter, Fuel Pump, Fuel Pressure Regulator, Air Mass Meter, Fuel Injection Computer, Timing Belt.

Aside from those, we've also done the following: Checked the engine temp sensor, and it was within spec. Resoldered the Main Fuel System relay and swapped it with a spare. Wwapped the Radio Supression Relay with a spare unit. Tested for vacuum leaks (none), and tested the functionality of the fuel injectors (fine). The in-tank fuel pump makes noise, but has not been removed/swapped/bench-tested.

I'm running out of options as to what's causing the fuel starvation. If you have any suspicions, guesses, or divine insight, -please feel free to post a reply. The only thing we haven't checked is the takeup sock in the fuel tank, and the fuel system hoses from the tank to the fuel rail. -those are about the only fuel limiting components that I can think of, but they're somewhat unlikely. I have not yet back-probed the fuel injection harness to see if there's a shorted wire.

Thanks and God bless,
Fitz Fitzgerald.
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'87 Blue 240 Wagon, 261k miles.