ANY suggestions on improving the gas mileage on my 2003 Grand Cherokee Laredo 4.0l six cylinder ?

pclaptop

 

What are you getting now?

 

11.3 mpg

 

How many miles on odometer?

 

As a point of reference:
I own a 2001 GC Laredo, 4.0(orig owner).
I have constantly monitored my MPG since 2001. On avg pure city driving, frequent stop and starts 12-14 mph. City and short highway excursions trips13-15 mpg. Long highway trips of 2-4 hours, 21-23 mpg. In November 2024 with 188k I replaced a new Jasper engine(a entirely another nightmare story), Now with 191.k miles. again meticulously monitoring MPG. Avg city driving 12-13, mixed city short highway trips 12-14.2 and long highway trips (110-220 miles)- 21-24 MPG. Of interest, when I run 93 octane my mileage seems better by 0.5-1.5 mpg- that’s just my estimation

 

@pclaptop There is definitely something going on with your Jeep. I have an 04 Grand Cherokee Laredo 2WD with the 4.0Ltr I4 engine. Everyday driving, a mix of surface streets and a little interstate I am getting 16MPG. On the Interstate I am getting 18 - 20MPG. I run regular pump fuel at 87 Octane. I try to stay with the better fuels, WaWa, Shell, Quik Trip and similar.

I suggest you do some detective work. Check your Air Filter, PCV Valve, Fuel Filter. When was the last time the Spark Plugs were changed? Do you ride the brake inadvertently when you drive. Is the Parking Brake fully releasing? Check the Brake Calipers to make sure one or more is not dragging. Check the computer for codes. A bad O2 sensor can affect fuel mileage.

Make a list and investigate one at a time checking them off as you go. It will take some time but I think you will get there. Good luck.