It is a 1997 with 140K, auto, when driving it gets in the upper range in 2nd & 3rd....feels like a misfire, lack of power...it has new plugs. Any ideas?

Use some fuel injector cleaner and also clean out your throttle body, check www.motorvate.ca for instructions..very easy.

check for knock sensor code...? this is what happened to me when I found the KS code.