'96's temp guage jumping around
 

My sister called me tonight and said the temp guage on her 1996 was "up in the red for like 20 seconds" and has been jumping around. I told her what to do if it happens again and said I'd look at it tomorrow.

Anywhere specific to start? I was thinking thermostat.

Thanks.

thermostat, coolant level (ie-slow leak so it's not reading well/causing a massive air bubble), and maybe a small air bubble that's getting stuck in the water pump at low rpm.