I have a 2002 Supra Launch with the 5.7 liter. I did a quick search and it's most likely air in the fuel lines (old cracked lines... ethanol will eat the lines from the inside out) or the accelerator pump on the carb (requires a rebuild kit which is about $50USD) or water in the fuel/carb.
Rebuilding the carb is not very hard, I did it last year and I'm just an average shade tree mechanic always looking for an excuse to buy more tools to "save money" ...
I also replaced all my fuel lines last year as well $$$$ and I only use non ethanol gas to extend the life of the new lines.
If you need pics of carb rebuild I can send you some.
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2019 Supra SA450
2002 Supra Launch DD (for sale)