Anyone know what the ECM perimeters are for closed loop?

I noticed that some of guys have engines that run relatively cool.
What is the standard temp t-stat for 4.0?

What kind of gas mileage do ya'll get??

There is a relationship between engine temp, closed loop and fuel economy.

 

standard t-stat temp is 195,my 87 runs from 190 to 210 at the hottest,thats in traffic.As for gas mileage,couldn't tell you, I have never really paid that much attention.I know this, it likes mid grade alot better.

 

I have an 87 xj with 33's and 4.10's. Temp guage always read around 200 mark. when I drove this on the street I was averaging a corrected 19-20mpg.