00 v-40 owner. here's the situation: start the car cold, it runs fine for 15 to 20 min. then very noticable power loss especially on hills. a/c on or off. cruise on or off. more noticable under 60 mph (probably because of less momentum) if this were a old car my first suspect would be a fuel filter or crap in the tank. any suggestions or similar situations?? dealer thinks i have an active imagination.

thanks
dave