1999 Baja 252, and out of no where the temp gauge is only reading 110. I thought the gauge was wrong or broke, but if you run it hard,m then you can see it move to about 130 MAX... I think the thermostate is stuck open, but 110-130 is VERY cold... Ideas??

First thing to check is the guage and sender and make sure they are matched.

I had same problem before and it turned out sand had the themostat stuck open.

was it running that COLD??

Ok, so took it our again, and everything worked normal. so for three weeks the thermostat was stuck open, andnow it works again???? guessing i should replace. any thoughts?

Yes