robertburnett
I have a 2002 grand cherokee 4.7 /245.75.16 with 2in RC lift. I want to know what i can do to get better gas mileage ? tks.bob
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nekko
Drop the lift to about 1/2" above the ground, park it, and forget about this piece of junk
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robertburnett
If you lay under it Bitch. Your probably one of those bullies i used to girl slap in high school. grow up
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nekko
Okay. Your Jeep already has fuel injection, but it is indirect injection. If you look at the attached dyno chart for this engine you will see that it never hits a "sweet spot" where the torque and hp meet.  This make for major fuel inefficiency. I would suggest looking into a different fuel injection system, and/or adding a low to med boost turbo. This, along with a PROPER tune / engine mapping will give you  a lot more horsepower AND better fuel economy so long at it is tuned with that in mind. And, of course, so long as you don't drive too aggressively.

The Bitch.
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nekko
The chartwykres_power.php.jpeg 
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cosmicfrog
The 4.7 was designed for torque. That sort of limits your mileage. I had the same year and model Jeep as you and it got fair but not great mileage. I did a tune up that the first two owners had neglected (170K on the original spark plugs) and that helped.If you have aggressive tread on the tires, that will hurt economy but help off road.

Standard economy tips will help, but you'll never get really good economy. Keep up on the maintenance. Plugs get forgotten. Back in the 60's, you had to change them every 6 months. Now, people leave them in there forever. Getting the ones out of my 4.7 was fun as they had tried to weld to the cylinder heads. Keep the air filter clean. Those high flow filters like K&N  do what they say they will, but I think they are a bit of over kill. Your engine will only flow as much air as it can flow. The only time they do any good is on something pulling a load at wide open throttle (WOT). A plain paper air filter changed pout every now and then does just fine. Get your suspension aligned. A front wheel with improper toe in adjustment is like dragging your foot side ways. It sucks fuel and eats tires up quick. If you're running over 35 mph or so, keep the windows closed. With the new radial compressors, the drag on the engine is less than the drag on the body of an open window. If you can run without the a/c on, it's even better. Around town it doesn't make much difference. Make sure your brakes are in good shape. A warped rotor or dragging caliper will slurp fuel like a pig.

Keep in mind that new, that Jeep got mileage in the teens. The best way to improve fuel mileage is to see your Doctor and have that lead removed from your right foot. I miss my Jeep but I was offered enough money it got for sale.
Honk if you love Jesus.
Text if you want to meet him.
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gben
I had the 4.7 in a P/U added a cat back dual exh and an Airaid inlet and filter watched tire pressures and used synthetics in all fluid systems ...added 3-4 mpg hiway and added power and responsiveness in town driving!
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