What causes a power spike/loss in an engine?

What is your question?

The check engine light came on, and the power on my car is spiking or something. The lights are flickering like power is up, then down. The speedometer is acting up, too. It's going up and down and then goes to zero, then flails up and down

What makes this problem better or worse?

The longer it's on, the worse it gets.

How long has your 1998 Honda Accord had this problem?

a couple of days