OK, figures the car starts acting up a day before the install. Actually its been about a week but its still annoying. Anyway, my A/F meter is hooked into my front O2 sensor (MY 99s have a narrow band front sensor) and its reading fine at part throttle/cruise, WOT, etc but at idle I'm not getting a reading. Plus, the car will idle fine (700 on the nose) and then drop to 550-600 for a second, sputter a bit and then back to 700. Now when the cooling fans kick on, RPMs rise to 800-900 and the A/F gauge starts reading again. Weird huh? I've also got a hesitation on part throttle/WOT transitions around 3000 RPMs that feels like a rich-run bog. This is not similar at all to the MAF failure I experienced a few years ago so I'm thinking the O2 sensor is about to give out (besides, its 92k mi original sensor). Thoughts?