DTC Code 14 is no IGF signal from the igniter. If you have solid ignition on both coils (assuming an older 1UZ with two dizzy's) then you need to test the wires and check for the IGF pulses with a scope. The IGF signal is basically the negative side of the coil so the ECU sees a pulse above battery voltagr every time it fires the ignition with an IGT pulse. If the ECU outputs an IGT and does not see an IGF come back, it assumes that ignition didn't take place and it shuts down the injectors to prevent fuel pooling. I don't have my Lexus book here, but on the 95 Celica, it would cut fuel after just 4 IGTs without an IGF.
I have the same problem with my 92 SC400. It runs great once it starts, but sometimes starts then stalls. Put a voltmeter across the fuel pump. It loses power a few seconds after the engine starts. What could cause this?
Could be a dodgy Fuel Pump ECU Ryan.
Next time it does it, bridge FP and B+ in the diagnostics connector to see if it fixes it. If it does, theres a good chance that the Fuel Pump ECU is going south.
It did it again tonight. I bridged the connectors as you specified with a multimeter set on the 10A setting. It stopped the problem. When I pulled the lead out of the meter, the engine would begin to die. When I plugged it back in, it would go back to normal. The circuit was pulling about 8A, which seems a little high?? Anyhow, what options do I have? Does anybody know where I can get a schematic fo this circuit to troubleshoot farther?