ok what would cause tachometer to be staying at around 2 or 2500 rpm after firing up engine, and soemtimes not doing that and sometimes unsticking and working fine ?

thanks for anything

 

i'm actually having the same problem. When i rev it up the tach kinda jumps, but you have to tap the gauge to get it to go back down. So if you find out a solution let me know. Thanks

 

Is this the factory in dash tach or an aftermarket tach? I had a similar problem with an aftermarket tach and after rechecking all the wiring to be sure it was tight and connected properly I decided the tach was bad, replaced it and havent had a problem since.

 

also

when i first got my car the tach would jump around, sometimes sticking at certain spots, and jumping in sporadic bursts rather than smoothly

all it needed was a good cleaning in the cap and a new rotor.

ignition modules will also cause that, but there will usually be drivability problems associated with it too