1997 Honda Accord Sick Speedometer and Engine Surging

I have a 1997 Honda Accord SE with 125000 miles on it. I'll actually b e one of those owners who can say I drove my Honda 400,000 miles. That's because by now we have just about replaced everything old in it. My speedometer is ill. It will stay at zero often and then sometimes work just right, but at other times it will jump about like a ping pong ball. When it is jumping around, the car seems to surge and like it doesn't know what speed it should go. The last thing replaced was an oxygen sensor as my check engine light was on. Just before that my transmission was replaced maybe 6-8 months ago. Any idea what may be causing the goofy speedometer and the surging? Thanks