Okay I got this car in running shape the whole.

Okay I got this car in running shape the whole hour test drive and the drive home and to the store no issues I started it and was coming home when I hit the street to turn on the main road my RPMs started to bug out went from 1500 up to like 5k 6k 7k did that like 2 3 times than car stalled started its self back up drove me home turned car off restarted and started and ran fine so I let it sit over night when out there the next day to start it and wont start. Has spark on all four plugs. Fuel filter was changed fuel looks good gets the engine the thing is when turning the car over the engine light goes off after two 2nds the d4 light stays light and it just keeps cranking and cranking no start spray a little starting fluid and it started but ran rough as hell checked the timing its okay the cam spins and I have spark with new plugs. I checked over all the grounds expect the tranny ground haven't found it yet. When cranking two the speedo goes from 0 to 15 or 20? Strange? I went up to 80 one time I think the computer is bugging out not sure this is my first Honda. It has 129 k miles car was running the day of test drive like I said and I didn't do anything to it just drove it like a baby getting use to it when it all started 1/4 mile from the house iv heard Honda run for ever so im interested in fixing this thank you for reading