The vehicle that I drive every day to work is not the greatested one to get good mpg. I need a truck, so I found a 92 S-10. It's a standard cab short box, it has the 4.3L V-6, 4spd auto tranny, 3.08 axle ratio. It has working a/c & cruise, thats about it as far as options.
It averaged about 24mpg on mostly hi-way commutting. I know these engines are very knock sensitive(pinging) so I run 91 octane all the time. Ok so I did a tune-up & advanced the ignition timing from 0* to 12*, which helps w/ making more manifold vacuum but requires premuim gas. Mileage improved to nearly 26mpg. I know this is a fairly big engine in a light mini truck, so I invested in a Gear Vendor add on overdrive, this combined w/ the th700r4 overdrive gives me nearly 50% overdive. The lowest speed I can go is 52mph at 1100 rpms, & it runs fine at that speed, at 30mpg.
The waterpump went out so I changed it from the oem iron one to a aluiminum hi-flow pump, went from a 192* to a 205* thermostat, which helps out over all mpg. The problem is the long warm-up time hurts my mpg. I did a full heater core by-pass during the summer months which helped but was impractical to do every year. I installed a 1500 watt block heater that works good. On large vechicles the warm-up really impacts mpg.
I average about 32mpg on my summer commute, taking the secondary hi-way at 55mph. Its down to 29mpg in the winter. You know a crazy idea I have been thinking about is if this truck body gets too rusty I could stip it down to the frame & see if I could put a 2nd get camaro fiberglass body on it, they have the same wheel base.
