thermostat??
 

Alright I just got off of work today it was in the low 50's grid heater was definatly working when I started it haha.. any way when I came to a stop and and go back 60 mph it would warm up to 199-200 for 5 seconds and cool back down, or if i gave er a little throttle it would gradually raise a little bit and then cool back down.. I was wondering yall's C.R. cummins fluctuate like this too n its all in my head or if its time to change the stats its a 06 cummins 5.9 with 131k help will be greatly appreciated

Cole