GM-GMC: 5.7 TBI high idle problem, vacuum hoses, chevy c1500

Question
Thanks for your time! I have a 89' Chevy C1500 5.7L TBI. Crane Compucam, Edelbrock Performer alum. heads, Edelbrock Performer intake, stock PROM and TBI unit. When I changed the intake over to the Edelbrock (the stock would not stop leaking), my idle speed would not come down past 1600 rpm in park, 1000 rpm in gear, brake held. I've replaced the IAC valve and sprayed around my TBI, intake and vacuum hoses with brake cleaner, with no change, up or down.
I suspect there may be a computer problem. I have changed out my PROM with an Edelbrock PROM back and forth with the stock PROM a few times trying to work the desired result (adjusting the timing with each change). I fear that I may have caused a computer fault (not PROM). Is there a way to check the rpm circuit of my computer or maybe even verify if the IAC valve is getting the signal required to bring rpm down?
Thanks for any help!

Answer
lets look at the facts.... ran fine before edelbrock parts?
changed pcm... no effect. The iac motor is a monitored sensor and with illuminate the s.e.s.light if malfuctioning.
I sugest that you continue to look for another vacuumn leak.... try covering the t.b. with your hand.... if it still runs you have another leak.  possibly a slipped intake gasket or end seal? ps   the is no rpm circiut