The other day, my distrib in my 83 Carbed Z28 got bumped and the timing got messed up. I hit it with the gun yesterday and noticed that the timing mark is all over the place, ranging from 0-10* at times. Also, the idle is irradic. Yesterday, it was jumping from 500RPM to 1500RPM. Today, it is irradicaly loping a couple hundred from base idle of 700. This happens both under load and in park. I then revved and it sounded fine but as soon as it came back down, it started progressively missing worse and worse to the point where it sounded like less than 4 cyls were correctly firing. The final kick in the teeth was right before it stalled, the distrib started smoking. Should I find TDC again and time it from there? Or what could this be? The harmonic balancer lined up perfectly when I timed the car a month ago after my CFI to carb swap.

 

You won't be able to set the timing well if it's not idling smoothly.