idles high after driving

Alright folks here we go.My 86 shelby has been upgraded to a 88 system,the engine completely redone.Here is my list then i will pose my problem.steel crank, t2 rods, forged pistons, file fit rings, 1mm over valves,ported exhaust,3in down pipe,46\63 turbo,spearco intercooler,40 over injectors,programmed comp,12psi boost,12 degree timing,60psi fuel pressure.The car starts cold with a fast idle then falls to 1100.that is great til i drive it, when the speed sensor triggers the idle rises to 1800.After i stop the car wont come down to normal unless the ac is on.I can restart the car and the idle is fine til motion.Is this in the computer? Please help with the last issue i have