Slow return to idle. Need help

[fns]

Motor: 2008 turbo hayabusa. This has been steadily getting worse and now dangerous to drive. (It did not do this for the first 2 years and I have not changed anything)
Problem: Rev the motor up above 6k rpms and the throttle body snaps back but the motor slowly or Lazy returns back to idle. (Car Idles fine).
Things I have tried to eliminate.

1. vacuum leak. (I sprayed starter fluid all around the throttle body and vacuum hose with no rpm change)
2. Pulled the intake off and inspected butterflies and they seem to closing properly.
3. Disconnected my throttle cables and manually tested the throttle bodys and same results. (Snaps back to close and rpm's slowly go back to Idle)

Possible issues (NEED HELP)

1. IAC "Idle air control valve" This motor does have the stock IAC that is just capped off by the throttle bodies. (This has always been this way) Maybe it still does something in the throttle bodies??
2. Just notice one of the injectors is leaking. Not sure how that would affect it?
3. ???Not sure where to go next....Fuel (I run race gas 104 unleaded) Fire (New plugs and upgraded coils) Air (New air filter)???

Thanks

[65chedderbob]

Im certainly no expert so I'd wait for some of the more knowledgeable people to chime in, but it sounds like you've checked most air related things so I'd guess it's fuel related. When you say an injector is leaking, where is it leaking at?

[Frank]

A Thought ...Have you checked the TPS (throttle position sensor) ? Possibly not telling the ECU to "shut down"

[fns]

The Fuel is leaking outside right at the fuel rail...(Maybe just o-ring, Or it may be leaking in the cylinder??)....I have check the TPS. I have the Power commander pcv-pti and It shows real time TPS settings.

[fns]

Well....Replaced the o-rings on the injectors and still have the slow rpm return??? It acts like a vacuum leak. I have sprayed a a bunch of starting fluid on all the intake parts with no idle change. I also have a smoke machine for finding vacuum leaks and my system is sealed tight?? Any other suggestions?

[fns]

Update.....I replace the o-rings on my billet clamp that holds the throttle bodies on the motor.....I think it fixed it. Just loaded it on the trailer and heading out to Glamis.

[Deranged]

Glad it got fixed!
Did you do a home made turbo set up for it? If so, please post pictures and component info!

Thanks,
Justin

[studio5o]

Glad its fixed too...also interested in your turbo info....thanks