I am trying to wrap my head around what you are saying....I understand how the sensors work and how the ECU adjusts the fuel map and timing based on the various sensor inputs but what I can't understand is why you would need to reflash anything if the sensor was cleaned and operating as it used to.....the ECU should just compensate to the new values accordingly. The way you are describing it, you make it sound like the ECU somehow rewrote some of the parameter data based on the bad sensor output. I'm not sure how that is possible......The only thing I can think of is after the sensor was cleaned, the ECU doesn't instantly revert back to the default values similar to your modern day car where it requires X amount of run cycles before it will internally clear certain fault codes and default back to the original settings. I wonder if they went in and cleared the data bank so it would default back to the original values and this is what you are saying when you say it had to be re-calibrated.......I wonder if disconnecting the battery for 30 minutes would have done the same thing.....sorry, I am just thinking out loud :big smile:Unfortunately some of you are only looking at the sensor. The ECU still has to be reset and other values cleared and some other stuff re-calibrated. I don't know all the other details but this ECU is more complicated then I initially thought and evidently if you don't have a BUDDs computer you can't do it.