On my dsm, I pulled the throttle body, removed any parts I thought wouldn't like solvent and dunked it in carburetor cleaner. The result was a lot of black stuff being removed - especially when I blew out the vacuum ports.

 

I will try and adjust my throttle screw to 1200 then reduce it with the software and see what that gives me...If it doesent sort out the problem i will take off the throttlebody and give it a good clean with carb cleaner and inspect for obvious problems...

Thanks for all your input guys...

 

i had the same ZzZz noise...however i dont recall my pedal was any stiffer...
also...i believe the HKS FPR is whats causing this...we both hae the same FPR...

 

^ true maybe the sound and stiffness arent related... coincidently the sound occurs during the opening of the throttle and could be when the fpr does its thing...