1991 4.0l sweet spot?

[nine-teen91stxranger]

im going to be hopefully starting a job here in the next few weeks which requires me to drive about 110 miles round trip.... and i was wondering whats the 4.0L ohv "sweetspot" for the rpms? should i be running around 2800 rpms or where? im hoping i can get some help here asap. because this 14 mpg crap isnt cutting it here anymore.

 

[Hahnsb2]

2200-2400 imo.

 

[nine-teen91stxranger]

thanks, so see about running her about 65-68 mph. im not expecting getting 20+ mpg, but maybe 17-18. it has 3.55 gears, and 29" tall tires, so if that changes anything.

 

[AllanD]

2200-2400 imo.

This has been my experience as well 2200-2400rpm

Which in my case is hard to do with my 4.10 gears... that's why I want to switch to 3.73s

AD

 

[Hahnsb2]

I tend to run 70-80 on the freeway which is 2600-3000 RPMs, it drinks fuel to the tune of 14MPG.

My old sploder had 3.27s with 235-75s, it desperately needed 3.73s, I'd typically get nearly 2MPG better by not using 5th.

 

[ronclark]

im going to be hopefully starting a job here in the next few weeks which requires me to drive about 110 miles round trip.... and i was wondering whats the 4.0L ohv "sweetspot" for the rpms? should i be running around 2800 rpms or where? im hoping i can get some help here asap. because this 14 mpg crap isnt cutting it here anymore.

I have a MPG trip computer, i do find 2200 to 2400 is a good rpm range on the freeway.
I am finding its not really the RPM range, but how much you have to press the skinny peddle at a given RPM range. if you start lugging her she starts drinking the gas fast.

My tank averages 17 to 20 mpg

75mph yields me around 17mpg
55mph yields me around 23mpg

Do you have a manual or auto?

 

[nine-teen91stxranger]

its a 5speed sorry, i thought i said that.

 

[pcollins]

My 97 4 liter was getting 21mpg running 2500rpm.

 

[holyford86]

2700 rpm at 65, getting 17.5-18.5 mpg in combined driving. truck is in my sig.