I had very similar symptoms when the TPS (throttle position sensor) went bad on my '97...
I had dropouts on accelerating, random high idle, sometimes it would upshift late, winding the rpms too high and shift hard.
Didn't set code until it got real bad.
Three torx screws hold the TPS to the throttle body...I noticed when I took it off, it had a slight rattle in it when shaken, like a bad light bulb. The new one did not.
After installing, and idle relearn, it was fine.
Cheap part, might try it if all else fails...