No matter what I do my truck stays in the bottom third in the temp gauge. It's been like this on 2 separate engines. The only thing I could think of is that maybe it's running to rich. But for it to be running that rich I would think there would be other more noticable symptoms.

 

More likely an inaccurate gauge, or a bad thermostat.

 

It was on 2 separate engines with different thermostats. And I've replaced the cluster. I guess that could be a possibility.

 

From a lot of reading on this site I understand the water temp gauges on these trucks aren't that accurate and a low reading is somewhat common.

Did you transfer the same sending unit from one engine to the other?
Are/were you using a 180 thermostat in both engines?

 

Yo
I run the 180 thermostat my truck has 430,000 miles on it it runs like a champ keep the 180 on it

 

There's a pinned or recent thread on fixing temp gauges. They have two coils with very thin wire prone to breakage; then your readings will consistently be off.