97 xj6 75,000 miles engine check light is on went to auto zone and it said coolant issue, i noticed that the temp gauge is just about always in the blue its like it never warms up...bad thermostat????

 

Very possible or a bad temp sending unit.

Does it take a while to start throwing heat out the vents when heat is selected?..That will tell you if the t-stat is stuck open.

 

its thermostat stuck open common on that model, be happy, you could have a v8 that tend to stick closed(alot) and make you overheat on the side of the road. Its easy to change right on the top of engine, takes about 5 min

 

Definitely sounds like your thermostat.. try replacing it, but I would only use OEM parts with something like that..