If my car only fire on 7 cylinders instead of 8 do that cause my tachometer not working right? I have a stock tachometer in my Buick GS400 1967 and it works good sometime and sometime not. I think it can have to do that the engine goes on 7 instead of 8 cylinders thanks.
If the misfire is due to the ignition not triggering, yes. If the misfire is due to something else--fuel, valves, spark but not across the gap (plug wire fell off, for example), no. Keep in mind that in some cases, a faulty tach can make the ignition misfire. Consider disconnecting the tach from the ignition system, and see if the misfire goes away.
Probably not. If the distributor and coil are working, the tach signal should be proper and appropriate for the RPM. If the ignition doesn't create a spark, the tach would not get the signal, so the needle might drop--but there'd be no spark to the plug wire from the coil.
