OBD I code #'s and bucking problem-

I have a 1992 Corrado SLC hooked it up to the VAg and got the following :
DTC recognized
0053 010
Idle Air Control Regulation Adaption limit not reached sporadic DTC

I have already replaced the following;

ISV
fuel pump
mass air flow sensor
intake tep sensor
Throttle position switch
#1 knock sensor ( asper VAG code readout)
Lower degree thermo and fan switch
radiator
All air hoses have been double checked and all are perfect.
So any ideas ? Is there a vacuum hose I have missed and do not know of? All the main hoses look fine. Car still bucks but it is sporadic and if you turn it off and back on, it runs fine.
Any ideas appreciated.
Jay