Replace the vent to the gas tank? An experiment- when the engine starts to "act funny", open up the gas cap, hear the whoosh, and then drive around some more. Engine acting normally = replace tank vent.

Check the fuel pumps- the TE has two. If only one is functioning normally, you will experience issues at less than half a tank. Replace both, not just one at a time, if you do not have records of their past replacement.

Check the rear rubber fuel line between the tank and the rear most fuel pump. That hose has a bend, and it can collapse or crack (drawing air into the system forward).

And of course you replace the fuel filter every 30K, so that is not an issue, right?

I would put "collapsed tank" as the last thing to check.