I got a call from my 4-year old yesterday telling me the 4-Runner quit running (he's a bigger gear-head than I am). My wife was backing down my parents driveway (pretty steep) and it just quit. She said it started back up without a problem, there is no CEL, and she had a 1/2 tank of gas. The only changes in the last couple of weeks are an oil change (went from whatever Toyota puts in it to Amsoil) and an air filter (went from paper to True Flow).

It's an '02 w/ 3.4, auto, and 110,000 miles.

 

With that said, it could be anyones guess. IMO, only time will tell.
Your oil change and a Trueflow filter would have no impact on stalling.
Sounds more like an electrical issue but without a CEL it would be almost impossible to know.

If you haven't done so already, other things you should replace is the fuel filter, pvc valve, plugs, and wires.