I have a 93 mustang 2.3.  I was driving home and my check engine light went on and the Tach started bouncing all over the place.  There was no audible change in the RPMs though.  After about 2 minutes the check engine light went off but the Tach kept bouncing.

I have twin spark so maybe something went out and I wouldn't know it maybe?

Any help is appreciated

hmm, interesting, sounds kinda like the computer or ignition module is having fun with you or something.

my best advice would be to get the trouble codes pulled and figure out what they tell you, since it triggereed the check engine light, there will defenetely be a code