Idle slow to drop
 

So i finally solved the high idle in my 87 5.0 with a new used throttle body. My bushings were wore and bad tps. Noe with the new tb with a cleaned iac and i havent touched the tps on it. I cleared the computer i comes down to about 800rpm but it takes a second or 3 which kinda sucks with my 4spd. Does it take awhile for it to relearn? What could it do to get that idle to drop fast?