Your themostat doesn't open until 195. Between 180 and 220 is normal operating temps.
The best speed for MPG is approximately 40mph; This is the minimum speed OD can be engaged at, if you were curious. With careful throttle management it's possible to maintain OD down to 35mph.
I am also doing some trialing for an EGR mod allowing greater EGR at cruise. This should provide a small increase in fuel economy at cruise and is easily done.
I have a 99 Blazer 4x4 2 door myself with some ecomods done on it. The dual mirror delete only has very marginal effects. I have an air dam, a battery relocation with a lighter battery, E-Fan, roof rack delete, and AC delete. I see high teen's to low 20's city and not much better on the highway.
The air dam.
Here you can see the mirror and roof rack removal.
