Thanks for the responses. No, it won't shift out of second under full throttle. There is nothing under the pedal, and if I'm going say 50mph and hit it, it down shifts into 3rd normally, so the switch seems o.k., and if I go almost to the floor without hitting the switch, it still does it. It is only in second that it won't upshift under full throttle. I hope someone else can chime in with some suggestions. Maybe there is a transmission guy around that has an answer to my delima.
I forgot to mention that the car just turned 62K miles. The previous owner was in her 70's and I doubt if she ever hit passing gear, so I don't think abuse is an issue here. All other aspects of the transmission are fine. It shifts perfectly except for this.