ATX slowly revs down after letting off gas

[zacritz929]

Im going to have my trans rebuilt and want to diagnose a problem with it. Before the trans broke if I floored the throttle from a dead stop and let of the gas at 5k or 6 k RPM's, the RPM's would drop slowly(almost like a m/t car). Every other a/t car that Ive driven would drop to 1500 or 2000 RPM's only a second or two after letting off the gas. What could cause this slow rev down?

 

[SHOZ123]

It's fairly common with the >OBDI & newer emission vehicles. But it is either the programming, a throttle plate not closing completely, an air leak after the MAF including vacuum leaks, or the IAC is bad. Basically there is more air than you want entering the system at closed throttle.