Hey guys, I have a 1999 Toyota Tacoma 2.7 4 cylinder 4x4.I got the truck with 80K, did an aoto Rx and I drive 10K per year. The truck has 90K, and I just put in Valvoline Synpower 1K ago. I drive at least 2 short trips back and forth to work, and I climb a pretty steep mountain for about 5 miles each way near where I live every day. When I do go over the mountain the truck gets to normal operating temperature. I occasionally haul my dirtbike around about 9 months out of the year. How often do you think I need to change and should I switch to conventional. Thanks to all replies.