The Tachometer in my 1998 sebring convertible 2.5 jumbs from 1 rpm to 4 rpm randomly or sometimes works backwards anyone have an ideal what might be wrong

 

Don't know if your model has this or not but run a test on the instrument cluster.

YouTube - Chrysler Sebring 2003 Test Sequence

That way you can see if you have a bad gauge or something is bad in the engine.

Is it just the gauge or are there corresponding reactions coming from the engine when the gauge is malfunctioning?

If it is just the gauge, it should be relatively easy to replace.

I had a bad camshaft position sensor that had ill effects on my rpm. May be you should look into that?

 

Ya I tried the instument panel test didn't help. I don't feel any problems with the engine just the tach.