Recently while driving the Speedster I was experiencing some issues with the motor hesitating or stumbling between 3000-4000 rpm. Under heavy acceleration I noticed the tach needle was being real sticky and would stick at about 3,000 rpm and would then become unstuck and jump to 4000 rpm or higher. I also noticed that the car would hesitate as well and not accelerate smoothly. Having just cleaned the entire idle circuit I knew this wasn't a carburetor/fuel related issue because above 4000 rpm there didn't seem to be a problem and if my carbs were having issues keeping up with the fuel supply it didn't seem like it would get better at higher rpms/speeds.
I decided it must be a spark related issue so I set about double checking the entire spark circuit. I checked the plugs and other than the little tips being a little loose they were fine. I tightened the tips up and made sure the spark plug wires fit tightly and securely which they did. I double checked the spark plugs wire to make sure they was no damage anywhere along their path and they were fine. I took the cap off of the Maganspark distributor and looked for wayward carbon issues indicating spark scatter and everything was fine. Small amount of carbon on each of the contacts which appears to be normal and those were easily cleaned with my finger nail. All wiring inside the cap was fine also. Reattached the cap and removed, inspected, and replaced each of the spark plug wires on the distributor cap. Checked the wiring on the coil and of the four wires one was very loose where it connected to the tab. I removed that connector and crimped down the wings of the female connector and reattached it to the male connector on the coil.
Took it out for a shakedown run and the tach was working properly and the stumble/hesitation in the acceleration was gone as well. I tell my tale so others will know that not every issue or fix is obvious and just a slight wiggle on that connector was enough to cause a disturbance in the force.
The photo shows which wire was the culprit:
