Just got my 88 GT on the road today. Noticed my tach is way off. Not sure if the tach is bad or if it is a wiring issue.it says I am idling at 1800-2000rpms. When I drive it and use the kickdown it goes off the end of the scale . Suggestions??

Is it possible someone has swapped in a tach for a 4 cylinder? A 4 cylinder tach will read 50% higher. What's the redline on it?

I believe the resister in the RC circuit is bad. Swap in another tack and I think you will be OK, or if you want to keep you tach I can repair and calibrate it for you.

Jack

I believe it is my original tach. It is a 6k tach. What is the cost to repair it , compared to buying another used one?

I don't know if the tach filter would cause those symptoms, or not. Maybe someone else can answer that. I have a good 86GT tach, but I don't it's backlighted lke the 88.

I am having the same sort of issue with my tach. I thought is might be a failing capacitor so I replaced it to see if that would fix it since it was less than a dollar, but I still have the same issues. http://www.gmtuners.com/fiero/fmods.htm
While I was in there I made sure all the connections for the instrument cluster are clean and corrosion free.
This weekend I will be checking the wiring.

Let me know if you find anything out.

tampalinc, I rarely find the capacitor goes bad. adm927 you have a PM, also are you going to go to "Run for the Hills" Sept 16?

Jack