1) noticed this first, my tach goes crazy sometimes. it runs fine and normal, but someitmes it just drops to 0 while driving, and if i rev it, it jumps up to where it needs to be.

2) more recently. Very rough on the first start up. takes a couple of times of just holding the key while it wants to starts but just stumbles.


maybe a coil? Distributor cap?

 

the tach going bucknutty may indicate an issue around the igniter. check the connections between the distributor and igniter for corrosion or moisture. also make sure they're are completely seated in the plug.

the second problem sounds more like a cold start issue probably related to the cold start injector time switch and/or cold start injector but could be a leak in the intake