It keeps going and going and going

[1slowdsm]

After my tranny install, I took the car for a test ride around the neighborhood. Then I was on my way to get my car wash and was on 65th in 5th gear when I noticed that my car didnt decelerate when I let go of the gas pedal. I went into neutral and my car idled at 3500rpms! so I skipped the wash and drove it to a parking lot, checked things out. Nothing seemed lose, missing or stuck. Then I drive to my parents house shifting like Im on the race track (no lift to shift) and once I get here. I went down hill, stepping on the breaks and in 3rd gear, the car's about to die then I went to do a u-turn and the car is normal for a couple seconds, then it gases and then goes normal. So I take it around the block and it's normal now....so far.

What's wrong? Im stumped, never have I ran into this kinda problem.