seat altea 1.6 petrol,engine jerking at idle

[mystic 8v]

hi,my friend has an altea 2004 1.6 petrol bgu engine code, but when it idles it runs okay for a bit then starts to jerk and hunt,i have checked for fault codes and non are logged.I have cleaned the throttle body and reset basic setting channel 60(erased learnt values first) i have checked for air/crankcase leaks all breathers okay,if the map sensor in the manifold is unplugged it makes no difference to the hunting,from my memory i recall audi a3 1.6 to have had the same issue,im thinking that the throttle body could be defective even though it basic sets okay,ive also checked the engine temp sender at running temp which reads okay,my friend said that its not so bad when the engines cold.Its not like a ht lead etc ist like a continuous hunt revs up then down constantly

any help would be great cheers.