I have a 1986 c4 that wont display the mph or the instant or range mileage left any ideas?

 

Welcome to the forum.
I have heard over the years that the LCD displays on the C4s can be a problem. I remember reading that there are aftermarket companies that rebuild them and you might check on that.

 

Batee.com. One of the best places to get your instrument cluster repaired. Check out the website, there's a wealth of info there along with parts if you feel up to fixing it yourself. I had Bryan repair mine the other year, it's worked great ever since.

 

Definitely, some rebuild them just try reaching out to them