Overlooked maintenance

Had to use my in laws truck for awhile while my car was in the shop. Found the trauck, 93 GMC Sierra, was sluggish and had 14 mpg hwy. I had the transmission flushed (not a simple filter replacement/fluid change) and the MPG went up by 2.4 MPG. WOW. Now the tranny works great. thought I was going to have to get a rebuild there until I saw the results.

Hope this helps.

How was the air cleaner? I fit's too dirty that impedes the flow of fresh air and can also reduce the fuel economy. Also were the tires properly inflated? All these "little things",including what you did in the first post can add up to an increase in a vehicle's fuel economy.

No change in anything besides the tranny flush. I had already completed all maintenance, flipped the air filter lid, new tires, and dropped the tailgate on previous trips. The route was the same and my driving habits changed little. All highway driving.

Had to use my in laws truck for awhile while my car was in the shop. Found the trauck, 93 GMC Sierra, was sluggish and had 14 mpg hwy. I had the transmission flushed (not a simple filter replacement/fluid change) and the MPG went up by 2.4 MPG. WOW. Now the tranny works great. thought I was going to have to get a rebuild there until I saw the results.

Hope this helps.
Never have I encountered a MPG increase when the transmission was flushed. I have to say you have improved MPG through other means, such as driving habits that you mentioned.