I have a 98 suburban with the 5.7 liter engine. Driving a careful 55 mph gives me 21-22 mpg on the level in Iowa, On hills and winding roads drops down to 19-21 mpg. Driving freeway speeds with the air running and keeping up with traffic going 75 mph drops me down to 17-19 mpg.
I am interested in knowing if I can do anything under the hood to improve mileage, Ive seen electric fans, synthetic oils for the gear boxes yet I do not want to venture into this area because I suspect I may be wasting money by getting 0.00001 mpg improvements, but then, I dont really know.
Also, can I do anything with aerodynamics to reduce drag....fold back mirrors (maybe this is extreme) for example, airflow deflectors..etc???
How about the daylight running lights, anyone know what shutting these down will do?
Any ideas?