AX15 problem: RPM will not drop

Hey all,
My buddy is having a problem with his AX15 on his 99 4X4. When he presses the clutch pedal down it will take about 4-5 seconds for the RPMs to drop. He usually shifts around 2800 and then it drops to 2500 right away then there is the long wait for it to go down to 1000. I've never had a 5 speed before so I'm stumped. He already changed the TPS and it made no difference.

I'd check the throttle cable, and make sure that it's dropping back to idle as soon as the pedal is lifted.

I think the told me that he couldn't replicate it while in neutral and not moving and that it only happens when driving. We'll check out the throttle cable.

Leaking clutch slave or master cylinder would be my guess.

Why are you holding the clutch in for so long when you shift? My AX15 does the same thing RPMs will not drop instantly.