Sticky throttle?

[evinX]

Ive been having problems with the old girl lately, and one is the throttle. I THINK.

 

When its sitting and is on idle, if I were to revv it, the revs would raise from 1k to 1.5k and stay there, all running faster. Now if we touch the stop on the throttle body that sits below the adjuster it goes back down. But wont do it normally. My dad thinks the mechanism is worn due to wear and tear. But we cant be 100%, when Ive just had a drive and its all warm and park up. Revs are high, its at 1200. If I turn it off and on revs are at 1k and lower gradually. How it should.

 

Help please people

 

Kev