I think the flywheel adaptation has been a serious hindrance in my previous efforts. I installed my new #1 O2 sensor today. After following the run/coast procedure and going through the x2 35mph trips, x2 50mph trips and x4 2200 rpm coasts, all sensors but the secondary air system have set to OK - including the o2 (which have never set before).

I've got another drive cycle question.

The instruction I followed, extracted from the Volvo TSB is that the engine need to be cool between attempts to set the drive cycle. Is that true?

Do I run the car through the cycle just once. Shut it off and let it cool down. THEN restart it until warm. Shut-down and re-run the cycle?

Previously, I'd run get the car warm, then run the cycle, idle, start over and re-run the cycle w/o shutting down the engine.

Has that been my mistake? re-running the drive cycle sequence w/o letting the engine cool - or that is that wrong? and the engine shouldn't be shut down between attempt to set the cycle?