So it's running while startup enrichment is on then can't run on your regular table? Is your warm up enrichment table reasonable looking / same as a diy base map? If it's truly lean check through your req fuel and be sure your fuel pump is staying on (I understand that's an issue on 1.6 cars?). If that's all good then you are likely (as you say) too lean so try adding fuel around idle.

Question: will it run longer / stay running if you pulse it into higher revs and keep it at say 4500rpm?

Yeah if i keep the revs up by holding the throttle bumping it kinda aroubd midrange like wawawawawawawawa in a fast motion with 3-5 hundred rpm up and down fast, it will stay running. I see your in woodstock. 905 962 7498, mind giving me a call?