Fuel pump relay & fuel pump inertia switch

I believe that the fuel pump relay, if there is one, is in the junction box under the hood with the fuses. I don't think that there is a fuel pump inertia switch.

Are you sure this is an inertia switch related problem? I thought that once an inertia switch or rollover switch trips, you have to reset them manually.

I'd think the first suspects would be a bad fuel pump, clogged or pinched fuel system line, or bad fuel pressure regulator, something in that area - when the fuel pump pressure and flow can't keep up with the injector demand at WOT, it'll act like the fuel pump or the ignition is cutting off.

I'm surprised that the OBD-2 computer hasn't set a trouble code. (Check Engine light.)

Hook up a fuel pressure gauge (with a long hose) to the test point on the injector rail, take someone with you to watch the pressure gauge, go out test-driving and romp on the gas hard.

IIRC the fuel rail pressure is supposed to go up when RPM's and fuel demand are higher - if it stays static or drops, the pressure regulator has problems.

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I recommend pulling the codes from the ECU before attempting any further diagnosis. Chances are, the codes will point you in the right direction.

I think the fuel pressure regulator is on top of the engine, attached to the fuel rail, and it probably has test ports on the input and output so you can see if it's the fuel pump or the regulator.

I've pretty much exhausted my stash of clues (I don't do this every day, but I know the theory) - Let's see if Ray or one of the MDT Techs that hangs out here can take over.

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I've seen fuel pressure regulators by the fuel rail and attached to the tank-mounted fuel pump. I don't know the setup on the T-100. The one by the fuel rail looks like a diaphragm-looking thing. As for the checking fuel pressure, I don't think there are test ports. The Toyota SST attaches with a banjo fitting installed in-line where the fuel line attaches to the rail - this method of measuring fuel pressure would work as long as you are downstream from the regulator.

The OP mentioned a check engine light - I'd start by pulling codes. I don't know if the T-100 has OBD II or not although you can look under the driver's side of the dash for a port that is shaped kind of like a parallel connector for a printer to a PC. This shape diagnostic port is OBD II and trouble codes can be read and cleared with a universal OBD II code reader.

If the diagnostic port is square, then the system is not OBD II. In this case, jump terminals TE1 and E1 with a paper clip and count the flashes. There will be a short pause between the first and second digit of the malfunction code and a longer pause between the first code and subsequent codes. A steady flash means that no codes are stored. Clear codes by pulling the EFI main fuse or disconnecting the negative terminal of the battery for 30 seconds. Keep in mind that disconnecting the battery will clear radio presets and clock time as well.

If its turbocharged (not sure of the car) it could be a fault with the actuator hose allowing overboost -> fuelcut by the ECU. Again, codes will help :)