What did you change with the tune up? Check for a loose spark plug wire or a loose plug. Make sure the distributer cap is tightened down.
Being that your engine light comes on and goes off could mean something that was touched during the tune up may be loose or something like that. Take the vehical to autozone or a place like that to have the engine scanned with a scan tool. I think their scan tool can get a code for the engine light. Sometimes however, their scan tool can only get a code with the engine light on--but if you are lucky the light will be on when you get there--or try to time it that way. Autozone will do this for free. A dealers scan tool will tell you the code with or without the light being on, but this will cost you around $60.
With 195000 miles have autozone test the ignition module and the coil, they will also do this for free.
Is this engine fuel injected? If so, how many injectors does it have?