Welcome aboard!
I'd replace the fuel filter, especially you don't know when it was replaced. They're really easy on the v6 compared to the 4cyl. A Toyota fuel filter will run you around $26.00 or so dollars! Also pull a plug and see what they look like, it has been 15k since your service!
I hope you get as many miles out of your 3.0 as I did mine!
Good Luck! Let us know how things work out for you! <img src="/forums/images/graemlins/kewl.gif" alt="" />