when i start my metro 3cyl. the engine rpms surge from 800 -3500 rpms, how do i figure out the problem? it also does while driving

Your TPS(Throttle postition sensor) is outta whack. A service manual will explain how to re-adjust the TPS. Also, i've noticed the IAC solenoid can cause this too. IAC=Idle Air Control valve. A service manual will tell you where this is. My GT was doing that, and I just unplugged the wires from it, and my idle instantly stopped surging.

My '93 Geo also had an engine surge before it went back down to normal idle. I suspected a vacuum leak and began searching all the vacuum lines looking for breaks or leaks. Found one and fixed it - surging went away.

Check for vacum leaks first. I don't know if you have an IAC but if you do don't unplug it. Clean or replace it. If all alse falls check timeing & comprestion.