Sticking/lazy tach
 

I have developed an issue with my '87's tach. It seems to lag behind what the motor is doing both on acceleration and deceleration. I took the car out and it ran great. I had replaced an 8 year old battery this month. I had never had an issue with the tach before now. I pulled the tach and the connections are good and looking at the gauge face it doesn't look like the needle is touching the glass. After reading through pages of posts I was wondering if this is purely mechanical and I should just send it off for restoration or is there something electrical that I should investigate.
Thanks,
Ken

I just got mine ('85) back from No. Hollywood yesterday. Same symptoms as yours, and it got progressively worse until it just died - well not really, it would come alive briefly if the outside temperature were within it's range - then die. No. Hollywood replaced the PBG (?) - and, upon request, disabled the upshift light...waiting for the weather to get warmer for the install, but all should be fine. (They did my speedo in 2010)
Bill K

Thanks for the quick reply Bill. It sounds like we are on the same timeline as NH Speedo did my speedo a few years ago as well. I have already emailed them.

My last failure was epic. I went 4 days at the Sebring advanced solo DE with no tach. That's when I decided to quit fooling around. (service was not cheap)
good luck
Bill K