Toyota 4Runner question

1999 Toyota 4runner with the 3.4L V6 125,000 miles. My problem. After driving 60miles during which the truck seem to be stumbling at hi-ways speeds. I shut off my truck and went into resturant for diner. On returning my truck had no power to even turn over the engine/battery completely dead. After getting a boost the truck started fine, I drove the car for 3 more hours without shutting it off assuming that the drive time would give it enough time to charge the battery. No such luck on trying to start the truck again the batter had no power to even turn it over. I got another boost/jump start which took 4 tries to start. Drove home cleaned the battery terminals and cable connections and now the truck starts fine, but continues to stumble or studder at hi-way speeds The truck has no trouble idling at lights or driving around town but seems to be studdering on the hi-way. When the studdering occurs the engine rpm doesn't seem to be changing on the tach. If you can help me solve this problem I will be more than happy to make a donation to your website.