For a while now, my car has been losing a great deal of power at the top of third gear. First and second gear seem to pull great, then somewhere around the middle to the top of third gear it stops pulling, and starts to kind of "shimmy". I got my Scanmaster and installed it this week, and did a few runs to see what I could find. I did a WOT run through third, when it started acting up, then looked at what it recorded. My O2 millivolts that it recorded were around 450. It's my understanding that this is extremely lean, is it? I'm getting ZERO knock retard though. Shouldn't it be knocking like crazy if it was running way lean?

Could it be that my fuel pump is failing at those high rpm's, and just can't supply enough fuel? I replaced the fuel filter not too long ago, so I doubt that's holding it back.

If anyone could give me any pointers as to what to monitor on the Scanmaster as it acts up, I'd really appreciate it.