Why does my car rev up when i am going down hill while braking

I think what is happening is that your car is just down shifting when you are applying the brakes. When a car down shifts to a lower gear, the RPM's will shoot up. When you are in the car next time, just put it in drive and go about 40 or so. Then drop it from D into 3 and watch your tach. You should see it shoot up when you down shifted into third.

Or. What is your RPM at before it jumps to 3000 rpm. Gas engines have more engine braking (compression braking) at higher RPM. Almost all new vehicles with automatic tranny's have a torque converter lock up to save fuel on the road. The PCM will unlock your torque conveter while braking to utilize the engine braking but this should not be noticable. Has the car had any other issues with the tranny, how is the fluid.

I was driving a new Accord EX down WVa's 5 mile 7% grade. I did not touch the brake when driving 75 mph, but when I took my foot off the gas the rpms when up to 3000. Is it ok to take it out of grear and coast to not reve the engine and burn extra gas? I averaged 74 mph for 37.5 mpg for 1240 miles. I did keep it in ECO mode. This is much better than an 2004 Accord 2.4 which would go 31 mpg at that speed.