Not sure what you meant by first part. Do you mean that the first fuel gauge read low and second gauge didn't read at all. It sounds like wiring. Firstly there's the connections. Any dirty/corroded connection will introduce a resistance that will give an erroneous reading at the gauge. Then there's the possibility of broken wiring with in the wire insulation. All connections should be cleaned at male and female end. Then there's making the right connections. Do a search as this has been covered many times.
The tach runs off the ignition coil and any problems usually usually stem from bad wiring in this area. additionally, the tach often stick initially until they get an RPM blip because the needle mechanically sticks at rest position and that position needs to be cleaned.
TR7 Spider - 1978 Spifire - 1976 Spitfire - 1988 Tercel 4X4 - Kali on Integra - 1991 Integra
