4 Wheel Drive/SUVs: 1998 Cherokee cooling., overflow tube, air pockets

Question
A few weeks ago I was in utah.  I was in some mountains on the freeway and whenever I would go up a hill the temp would rise... then if it got just above 210 the gauge would jump up to 260 or whatever the max is then as I continued to drive it would drop right back down to 210.  It wouldn't gradually rise but it would jump from one to the other.  No in between.  I put a new temp sensor in it but I haven't been in that kind of country yet so I don't know if it made a difference.  What do you think?

Thanks!

-------------------------
Followup To
Question -
You may not have the answer to this but I can't find anyone else.  How do I make sure there are no air pockets in my cooling system?  It runs at 210 all the time and I wonder if there is a air pocket.

Thanks,
Dan
Answer -
Dan,

This is common on most of the newer Jeeps.  I have a 94 Wrangler, and 2000 Grand Cherokee, and (according to the gauge), they both run at 210.  If you had a cooling problem, the temperature would not hold at a steady temperature, and if overheating, you should notice fluid blowing out of the overflow tube.

Carl

Answer
Dan,

I think that you found the problem.  Normally, when a vehicle is overheating, you will see the temperature rise slowly when under a heavy pull, or when running the engine at high RPM's for extended periods of time.  When this occurs, the engine should cool down fairly fast when you go back to level ground, or head downhill.  The rapid meter movement is an indication of an electrical problem, such as the sensor, or a faulty connection in the gauge itself.

Carl