At high speeds rpm's will not decerase when i let the foot off the pedal at high speeds?

(2011-02-25 15:20:09) 1. tommaso Says: Hello, I have an automatic 1998 Trans AM. At high speeds sometimes my car's rpm's will not decrease when I let off the throttle. This can happen if I am on the expressway and increase to like 65mph and then wish to coast. I let my foot off the gas and the rpm's will not lower to like 1k rpm; instead they will stay at 3k rpm or 2.5k rpm unless I hit the brakes.

Is there something wrong with my transmission or even my engine?
Is this something with the idle or perhaps my tranny.

Note: I have an auto tranny, but it has a boot cover over it. I guess the person before me put this in. I think the gear pattern form top to bottom is Park, Reverse, Neutral, and then there are two drives.

Hope this helps...2. cjo84070 Says: Sounds normal to me. Try pushing it into neutral and see if it drops. If so it's normal.3. Savannah Guy Says: The most likely causes are the following:
1) throttle body is gummed up enough that the throttle return spring doesn't move the butterfly on its own - get some throttle body cleaner spray and clean it out good.
2) throttle cable needs lubrication
3) throttle return spring weak or missing
4) accelerator pedal mechanism needs lubrication

I would try all of these first since it's cheap and you can do it yourself. Tag: At high speeds rpm's will not decerase when i let the foot off the pedal at high speeds?