I drive Like Grandpa, 18-19 mpg (75% highway). I have a stock 1994 S-10 X-cab, 4.3L TBI, Automatic w/ OD, with nearly no mods at this time.
I am about to put it in the shop because of low power at 50-75 mph in Overdrive, and an occasional “check engine light” and varying idle speeds when stopped.
The trouble is, when in Overdrive at 50-75 mph the engine seems to be struggling. It goes into passing gear for even the slightest uphill, but Regular Drive “D” seems to over-rev above 50 mph. It seems to have a very tall differential but I am not yet sure just what ratio it is.
Two days ago I ended up with oversized snow tires on the rear (235 / 75 / 15). They lug the engine a bit more during acceleration, but it looks like they may allow me to stay out of overdrive at 65 mph. Which is actually about 62 mph on the speedometer now.
I am wondering about,
Changing base spark timing to try for “power band” at 65mph,
Getting a chip, (but which one?)
Going to very small tires and using overdrive,
Hiring someone to change the rear end,