RPM gauge not steady, yet RPM's are solid

[scottinalaska]

What causes this bouncy needle. It mostly happens at idle where I am sitting at 800rpm and the needle will bounce up to 1200 and back again, yet the engine sounds very solid. It is more solid as I rev it, but the needle doesn't stay dead on at all like other gauges I have observed. Thoughts?

 

[FlyingEagle]

For giggles, unplug your transistor pack and tell me if you see green in the connections or if the plastic housing is broken and allowing any possibility of moisture intrusion.

Still using the 1G 91+ transistor assembly I assume?

 

[scottinalaska]

Man, I'll assume it is still the original...but I don't know where it is located. Is the transistor pack another word for the coil pack?

 

[tektic]

Something is from an older model coil pack transistor or ecu . Check part number on ecu.