I was sitting at a stoplight today and noticed that my tach was not holding steady. It could not decide if it was 500 RPM or 1100. Later in the day, it was reading zero. As soon as you hit the gas, the tach seems to read accurately, and for most of the day, it did not fluctuate. I have suspected for a while that my distributor might be bad and could be the cause of my hesitation issue. Any thoughts on this?