What's this seem like to you?

[Five O]

Driving today, had it in 2nd gear... car started sputtering but the rpms were still just under 2k. It bounced back after this and the car then drove itself, maintaining a steady 1800/1900 rpms or so and when I threw it into idle at the light when I got there the engine kept going at this rate for a minute. I revved the engine by pedal then it dropped back down to where it was staying at while revving, and dropped to idle after a minute more. Car didn't do it again after that but it freaked me out... I have a new fuel pump so I'm hoping it's not that, but I think it might be related to my issue of idle voltage surge since I replaced the alternator already and it still does that slightly.

I'm no mechanic, but it seems to me to be maybe a bad TPS or a bad ground somewhere? What do you guys think?