First of all...Thanks to all of you with your extremely helpful insight to my sensor problem. Thought I'd share an observation or two. Using a tip from a forum member, I purchased a 14" 1/4 drive extension and flexible 12mm socket. Unfortunately, the extension was too thin to withstand the torque needed to break loose the bolt. So instead, I used a 10" 3/8 drive extension, universal, and 12mm socket. However, I did use the 1/4 drive socket and extension to unscrew the bolt the rest of the way.

Once the bolt was completely unscrewed, I used a flexible spring loaded "grabber" to fish it out (wish I knew the name...it has a spring & plunger on one end that, when depressed, pushes out 4 wire claws on the other end...release the plunger and it retracts the claws which grab the bolt). From here I pulled the sensor and harness out into the open where I could disconnect it. To install the new one, I just reversed the process...With a long screw driver I played with it a while, nudging it to line up with the bolt hole. Then used the grabber to place the bolt down through the sensor. Gently placed the 1/4" drive socket (so as not to disturb its lined up position) onto the bolt. Hand tightened the bolt, and gave it a good crank with the 3/8" ratchet/socket. I wish I knew the correct torque requirement and hope I didn't go too far. Anyway, I came away without a scratch...Couldn't get my hand down in there anyway.

The test drive said it all. The hesitation (between 2K and 2500) is gone...Nice and smooth acceleration.

Hope this helps someone out there. Thanks again.