I just installed a 75mm throttle body and SR aluminum upper plenum on my 2000 GT. Engine itself is stock to my knowledge with an x-pipe and Flowmaster style exhaust. The only other add-on is an SR cold air intake. My problem is that now my throttle will stick slightly open and idle high if I just step on the gas a little like when taking off slowly. It is a manual transmission by the way. I have the return spring attached as its supposed to be. When it sticks like this I just have to hit the throttle quickly and it will back down. While messing with it I thought the TP sensor was causing it to be jammed or the throttle plate shaft was sticking or binding. But when I was messing with the throttle when the engine was turned off the throttle would consistently close and go back to the stop and it felt like there was plenty of tension on the return spring pulling the throttle back. So why is this happening when the engine is running? Is there too much air rushing thru the throttle plate keeping it from shutting? How do I remedy this? I hate to put a stiffer spring for the return because all that will do is make the gas pedal harder to push and I really dont want that. Anybody else experience this? Any ideas on how to stop it?