Misfire or tach or other electrical prob?

[nola mike]

So ALMOST running perfectly. Runs fine at speed. Noticed that sometimes (seems like the end of the day), when idling, the tach starts bouncing around, between 700-1400 rpm. The engine runs rough when it does this. I'm not sure if i'm misfiring, causing the tach to bounce, or if my primary problem is in the tach or wiring, or coil, or what. I did notice that my voltage gauge reads about 1v lower than actual voltage, and that occurs because of my resistance wire. When i disconnect that, I read true voltage at the gauge. I'm getting 4.7 volts at the coil; i haven't checked the actual resistance of the wire yet. any thoughts on how to proceed?

 

[nola mike]

Re: Misfire or tach or other electrical prob?

anybody?