I never spent much time messing with the 87. I only got that for times when I'm out in the boon docks hunting and can't get 91. I want to get the 91 dialed in first, as that will be my preferred tune.
I just pushed the heater hose out of the way and dropped in a long extension from above the intake to take the bolt out. On my truck, the bolt for the sensor is up by the front of the engine, the electrical connector/connection was the hard part for me. I had to lay on top of the engine and wedge my hand back behind the engine, on top of the trans bellhousing and feel around until I found the connector. Not fun but doable.
