Over Rev/Rev Hang

[YoungOne]

OK so I'm not even sure what you call this so don't know what to google. I'm planning to do a bit of a restoration of my fathers GF8 WRX and the car has an issue where the engine continues to rev for a split second after you come off the accelerator which would be great to fix. I've also encountered this on a mates GC8 WRX RA (non Sti) however it does not appear to happen on the STI models I've owned. Does anyone known what causes this or at the very least what its called so I can google it? 

 

Thanks

[calebwrx]

On some new cars it's a function of the ECU, apparently it's to do with emissions output. https://forums.nasioc.com/forums/showthread.php?t=2664570

On older cars I think its the flywheel that has the biggest impact on how much rev hang there is. I think the heavier the flywheel the longer the revs hang for, are you used to driving STIs with lightened flywheels at all?

[Batbaruman]

calebs probably on the money there, but just looking at it from simplistic point of view, could it be aged springs on throttle body or sticky throttle cable?

[YoungOne]

car has been owned by my father since new (MY00) and has done this from the moment it came off the lot so its not a wear thing, engine is completely standard, its a cable throttle which I think would rule out the ECU?? 

 

Maybe it is the flywheel, hadn't even considered it

[calebwrx]

How does the throttle application feel? Is the pedal smooth when you press it or does it stick? Could be that.

If I'm slack/lazy with my gear changes then my car does it as well, you might just have to adapt your driving style to the car