The spark plug was an unhealthy sooty black, but otherwise fine. Replaced it with a new one nevertheless.

Without removing the crank position sensor, its resistance is within spec at 236 ohms. The injector coil resistance is within spec at 11.9 ohms, the primary coil resistance is 4.1 ohms, the secondary coil resistance at 13.2 ohms. The airfilter is fine.

When I switch the ignition on, fuel pressure is delivered for a short while, <3s, then the pump switches off. Strange, I would have expected it to remain on when there's no pressure in the supply line to the injector? I have no way of testing the actual pressure. The airfilter is clean. The air temperature sensor measures 2.31 kilo-ohms (drops to about 1.7 kilo-ohms when I warm it to body temperature), while the manual calls for 2.3 ohms. Since it is reacting, I take it that the ohms in the manual should be kilo-ohms?

The TPS connector is just too difficult to get at, at this stage of the game.