I'm working on reviving an 87 TR that's been sitting for a few years. I've done the spring cleaning stuff, and have noticed that the engine shuts off during the 1-2 shift if I'm at WOT.
Sounds electrical...start car and wiggle harness at;
Ecm
Battery (pos post and starter)
Ground (neg post, engine block under turbo)
Main bulkhead connectors under wiper motor
Fuse block
Orange ecm wire at battery
Also;
Try another battety
Battery cables touching down pipe
make sure chip and calpac seated in ecm
Ill post more as I think about it
Follow the hot wire from the battery to the started and see if you can find a burned spot from contacting the exhaust while subjected to G forces.
then get under the car and give the fuseable links a tug and see how many are broken off of the ring terminals.
There's grounds on the back of the passenger side head that like to get all oily and stuff too. When they act up it's generally not Gforce related though.
Next time you have the tank down, modify the hanger and let the pump drop down till the sock is just touching the baffle. That'll give you access to another 1.8 gallons of fuel and more stable pressure when running low.