I agree. Anything thing under 185 will cause the truck to open-loop the fuel trying to warm up. Hotter is better, 210 is perfect.

He replaced the sensor and said it fixed it... no, I don't think it did. At this point, it's not about the differences it about a faulty thermostat. Once that is replaced and your temps are back to 190+ ECT, then look at the difference.... until then, your wasting your efforts on looking at EOT/ECT.

Missing is another issue. Have you read the codes?

 

Sorry I should have stated since changing the coolant sensor my FWT and EOT temps have been in the 175 to 188 degree range, unloaded at interstate speeds. Before having this problem the only time I've seen 210 is towing at interstate speed. Should the temps be higher than this? It does seem like my water temps rise faster than the oil temp.

My cel never came on, I checked for codes using the SGII but there wasn't any.

 

The ECT should be at least 188, but 192° is the factory setting of the tstat. If your not consistently getting to 190° or very close.. or more, change it.

 

The factory t-stat in my 05 always ran between 198 and 204. Same t-stat in it for 10 years.

 

I will change the thermostat, is there any particular brand I should get?

 

OEM in my opinion.

 

I changed the thermostat with a motorcraft unit. All seems to be ok as far as temps go. My eot and fwt are staying about 190 range now. As for the miss it's still present. I will post another question just for that.

Thanks for the help.

 

Diesels like to run closer to 200*. I installed the Mish-moto and Brute loves it!