I had the problem of the IM monitor for the heated o2 sensor incomplete for over 1200 miles after replacing the engine in my s10. I changed all 3 o2 sensors and in 2 days of driving all IM monitors are now complete. I read that when the heater circuit gets old it can take a really long time to clear. For the price of 3 cheap $12 sensors on ebay it was well worth the money to be able to get an inspection sticker.

 

The CORRECT cold start is to have AC and defrost on AND PUT THE CAR IN GEAR for the 2.5 minutes! Worked like a charm for me after seeing a hotshot mechanics reply on a different thread. Your welcome.