Well I PB blasted everything and let it sit for 2 days. All bolts are off except the inside bolt on the outside sensor. Cannot really see it too well but it is very crusty and the outside nut was rotten too but it came off with a 10mm after a little effort. The inside one is really bad. I have tired every kind of wrench and size wrench known to man. I have even tried needle nosed vice grips to no avail. 1.5 hours later, I am at my wits end. That is a very tight spot and I am wondering if any of you have any ideas. That little heat shield really makes things difficult. Why is it only on the outside sensor.