My car seems confused. Whenever it's running poorly or differently, I find something with my OBD reader that isn't right. I recently installed an OEM MAF sensor after semi-frequent issues with the old one. But, just like the old one, it worked great for only a few days. Fuel trims were right at 0, then gradually started going negative. Again. Yesterday LTFT was at -8.9%, so I unhooked the battery, cleaned and replaced the MAF sensor and it went back to normal. Today, my LTFT started trending negative again and I noticed my MAF grams per second reading was inconsistent and unsually high (around 5.6gps at idle.) I also noticed my downstream O2 sensor voltage was fluctuating. All sensors were "ready" by the way. The O2 would drop as low as 0.08 and get as high as 0.7. It wasn't fluctuating as fast as the upstream, but it would not stay the same for more than a couple seconds. I really don't know what's going on. Can any of you make sense of this? I'd really appreciate it.