I would put your car on an obd2 scanner that reads real time sensor data. See if scanner reading matches or differs from what the tach reads. If the reading is different, then circuit card in tach is probably bad. But check your wiring from pcm to tach just to be sure.
Ah you say you don't have a wiring diagram. 96 factory service manual is available for download in 4th gen section. It shares about 99% of info with your 97.
Or if you insist on 97 wiring diagrams, get them at BBB Industries- Premium Alternators, Starters, Power Steering Products
Ah you say you don't have a wiring diagram. 96 factory service manual is available for download in 4th gen section. It shares about 99% of info with your 97.
Or if you insist on 97 wiring diagrams, get them at BBB Industries- Premium Alternators, Starters, Power Steering Products