Garyss

Any ideas where to look 1988 tach reads 7000 rpm when running engine or when ingnition is turned on

931guru

bad tach

JustinL

Try unplugging the flat 8 pin (I think) connector on the wiring harness in the passenger floor area. You will lose a couple other gauges and some warning lights might pop up like oil level etc., but if that drops the gauge to 0, then you know the signal is bad. If the gauge stays pegged, then it's on the gauge side.

https://members.rennlist.com/tholyoa...wap_wiring.htm

GPA951s

Give it a good smack on the top of the dash… once in a while if my car has been sitting for long periods of time it doesnt work.. smack the top of dash … and all is well…

Swedge

Exactly, whenever mine sits for more than 24hrs, the tach sticks @ 2400rpm. A quick rap or two with the palm of my hand releases the needle and it reads normally for the rest of the day. Obviously this might not help your situation, but worth a try