My tach never goes above about 2k. At 55 mph, for example, it reads 1500....Idle says 400. There's a faint oily look to the face right around the two screws in the middle. Sending unit was replaced some time ago to no avail. Hmmmmm. TIA, folks!
Paul

 

not sure, but i think i read that its the trailing igniter, might swap the two around and check, or do a search first,,,,,good luck,,,, http://mrmazda.members.atlantic.net/cfaqtext.html

 

Tach feeds from the negative terminal from the trailing coil. Positive about this.