Hi there take it for a run and when you get home leave it running and see if the gauge rises then, a previous owner may well have took the center out of the thermostat. I have seen this before as a safegaurd after hgf repairto keep the engine cooler but all it does is keep the engine on choke longer and the engine never gets to its running temp hence using more fuel, if you get a new stat get the two O rings aswell.