Contour Enthusiasts Group Archives Forums General Troubleshooting Throttle hang @1500 RPM

96 SE with SVT UIM and optimized TB.
Problem started after reinstalling the SVT parts for the second time. First time car was fine, with the stock SVT TB. I optimized the TB months ago and wondering if I reinstalled the TPS wrong which is causing the throttle hang? No CELs. I have the throttle hang fix installed and it does help the RPMs fall faster till it hits 1500 rpm or so. There it can hang for up 10 seconds or so before coming down to 800 or so.
I took off the TB off today and took it apart again, same problem. I have installed two IAC's, I have my original in there now, they both work the same.
Opinions please.

I have searched back to 2003 reading about this hang. Bradness wrote about not using flathead screws during the optimzation of the TB because it could cock the plate in the bore. I do see a fair amount of light shining trough the closed TB but no more than my cleaned unmodified 54 MM one. I am pretty sure this isn't the cause of the hang. When I start the car from a cold condition the IAC seems to control the car normaly, Idle comes down to < 1000rpm. The hang only happens after you accelerate above 1500 rpm. With the throttle hang fix plug installed, it definitely helps with the rpm drop from above 3000 rpm. Should have installed this yrs. ago, also stops the moose using my original IAC, I have installed again.
I did reuse my UIM gaskets and this has me thinking to check that area.