I took my car out for a drive today and noticed that in 5 gear the tach needle was bouncing back and fourth about 1k rpms. It only did it in 5 gear and if I was staying a constant speed or let off the gas to slow down. If I gave it gas it would stay constant. My speedo also bounced slightly when the tach did. The only thing I have done to the car lately is installed a fmic and relocated the battery to the bin behind the driver seat. Any help anyone could give me would be appreciated.

 

This is a pretty common problem. Please search before starting new threads.

In order to fix this you'll need to remove the cluster, take it apart, and replace some capacitors (or resistors maybe, I forget exactly).

Like I said, SEARCH instead of starting a new thread, and you'll find your answer.

EDIT:

Ah screw it, I searched for you and found this in less than 10 seconds. See what SEARCHING would get you?

DIY Repair to RX7's Tachometer Solder Joints
http://www.clubrx.org/Media/FD_tach_repair.pdf

 

Thanks