4.3 in 71 getting 19 MPG?!?!?

[70rs/ss]

Originally Posted by Yamaha74

I had a 2003 ZR2 and it was consistently getting 16-17 miles to the gallon on the highway. Pulled a 2800 pound enclosed trailer once and got 9.5 mpg. The next week I traded it in for a 2003 GMC Sierra 5.3 litre 2wd and it is getting 18-19 on the highway and around 14 pulling the trailer. Yes I gave up 4x4 but I have a lot more power and room now with the full size. Plus with a 6 month old kid there is a lot more room in the extended cab of the full size then the ZR2.

My wifes 2004 trailblazer 4x4 is only getting 15-16 mpg in the city and have taken it on one small trip that was 75% highway and we only got 17 mpg. It is supposed to get 16 city and 21 highway. It has the 4.2 litre inline 6. I am not happy with the gas mileage at all.

My Yukon XL mentioned above is a 4X4. The thing we are not mentioning, but that is important is tire size, axle ratio, etc all of which have an effect on milage as well as flat roads or mountains. My Yukon has the 3:73 with 285/50/20's, she is a pig from a dead stop but you better look out once I get rolling.

[Huck]

Had a 91 full size with 4.3 and auto--got 21-mph hwy. My 2000 Z71 with 5.3 will get 21mph if you keep it under 70---even with the 373 gears. The 4.3 is an excellent motor but expensive for a rebuilt. Have not heard many raves about the inline. I personally have never had luck with an inline GM 6 going back 40 years. Keep in mind the 4.3 is a 350 less the last 2 cylinders. My 91 had adequate power for normal use and I was very pleased with it for 135000 miles.