06 24ssv water temp issue

[Broke Pilot]

Hey there, while we were out yesterday my water temp gauge starting acting weird. We were headed back to party cove on Conroe and was on plane running around 3700RPM... I started feeling what felt like cavitation (kind of pulling the boat back) off and on as we went over a shallower spot in the lake, I figured the currents were swinging and pulling on the boat. When I looked at the helm I noticed my water temp gauge was around 130*ish. It never got back above that mark the rest of the day, but the boat ran just fine.
What do these 340 engines normally run temp wise? I see online people sayin 140-160*, but aren't the thermostats 180*?
So in Yall's opinion, should I be looking more at the temp sender or the thermostat? I'm going to replace both, but I wanna do it one at a time and figure out of the t-stat stuck open or the temp sender is dying... Thanks!

[CJD]

130 is too low. The factory thermostat is about 165 degrees. Could be the thermostat, sender, or gage issue.