'00 Siena Won't Start after running for a while

Siena won't restart after it has been running for a while. Running around town, doing errands........if I stop to run into a store for 5-10 minutes and come back out, car will not restart right away. Exhibits low idle, cuts out. Try a couple more times.......same symptoms.......must wait in van for 5 minutes or more when it will start up like there has not been a problem. Otherwise, no problem starting up in the morning or if sitting for a couple of days. Battery is fine. I run fuel injector cleaner thru at every oil change.

I have the same problem with my 02 Sienna. Did you find what is wrong?

Wes