My newly acquired R16 (TL auto) [I will post separately on its acquisition when I get this problem sorted] is suddenly idling way too high (approx 3000+ rpm). I have replaced the return spring with a sturdier/stronger one and having mucked around with the throttle stop screw and the volume control screw. I can get it to idle about right with the engine at operating temp, BUT, I then take it around the block a couple of times and when I get back the idle has returned to the 3000+ rpm. If I then take off the air cleaner and start mucking around with the throttle stop screw and also the volume control screw I can get it back to an appropriate idle speed but the settings are basically what I started with and again the high idle will return after the next blast around the block. I don't think the kick down cable has anything to do with it as the gear changes are pretty normal and it will kick down on command. I am suspecting something is worn inside and jamming the throttle open. However if there is some sort of external linkage that I might need to try and tackle or something obvious I might have missed I would be grateful for any suggestions. I am best described as a K-Mart mechanic so please don't get too technical with any responses. Many Thanks in anticipation.
(I fear my next trip may be to the fine young Tonny Goode at Linton's Garage, Glenelg.)