Could his coolant temp sensor possibly have an effect on it?

 

Could be, but air in the system is the most lilkely culprit. The system seems to be notorious for this.

 

Well over the weekend I bled the system for about 45 minutes and didnt really see too much air evacuate. I have a new 195 deg T-stat to install yet too. Interesting thing is that since it has warmed up compared to last week my heat is warmer and the gauge is reading a little bit warmer too. I know the PO did use the truck for towing so it is possible that he did throw a lower temp T-stat in to keep things running cooler.

 

I had problem like this with a chevy work truck i changed my coolant temp sensor, clutch fan, new thermostat, and had my dad flush the system it worked a lot better but i think that truck had a clogged heater core in the end because it still never got nice and toasty just warm