Engine/Transmission (1998.5 - 2002) Transmission Downshifting

[THoltz]

When speeding up from a relatively low speed, such as when making a right or left turn onto the interstate merge lane and giving 'er a fair amount of "gas" pedal, the transmission will downshift and then upshift again in a second or two. It recently started doing this. Any ideas? Just looking for a place to start. Thanks for any and all help.