just reading up on this thread for my new to me 06 1300 with 22K and is experiencing similar temp reading. Looks like i need to test a few things.
In the driveway idling she warmed up to 3 bars at 37 degrees. I rolled out of the driveway to 40 mph and she dropped to 2 bars. I hit the highway (60-75) and she is toggling between none to one bar. I get into traffic she bolsters up to 2 and 3 bars. i then roll on up to 40 mph and drops to 2 bars. Based on the reading you all have provided it may/may not be a bad t-stat. Time to roll up the selves and do some digging.