Daverig

I have a 1999 jeep grand cherokee limited 4.0 and get 12 miles to the gallon in the city with a new engine in it. Engine has about 4,000 miles is that normal to be getting 12 miles to the gallon? The jeep has quadra track 2 and I drive the jeep on 4 wheel all the time, so my question is if I take it out of 4 wheel and put it in neutral will I get more mile to the gallon or will it mess up the transmission?

GreaseMonkey17

with the transfer case in neutral you'll get infinite mpg's lol however the vehicle won't move with TC in neutral .

dave1123

I would say that's about normal city mileage with Quadratrac.

Daverig

thanks

Daverig

thanks

GCWJ

With a 4.7, zero is not that far off, either

In all seriousness, with the 4.7 and a qt2 I have an average right now of 16.4. It's been as low as 14.6 at times, but when I feel that driving conditions haven't warranted the number I see I'll reset it and let it find a new average. Like between winter and summer, I'll believe 14 in snow and ice on streets but no way is it doing that bad on dry pavement at 70F.

I think I read that the OP has the same tcase I do, right? Quadratrac 2 and not the Quadratrac? If so, 4 all-time is the standard gear, where most of the time it's got a 100% torque bias to the rear, until the rear slips, when torque will gradually transfer to the front according to the degree of rpm difference (i.e., the degree of slippage). Essentially, whatever the OP is getting for mileage in that setting is what he's gonna get in his conditions and driving style. I doubt he'd get anything better if he swapped to a 242.

Edit: OK I re-read the OP. Disregard most of the above (leaving it for posterity). With a 4.0 in city driving he should be getting way better than 12. With my V8 I am getting 16 or so as above. I think the OP might like to see if there's anything that can be done with the engine or maybe reset the average mpg to get a new reading, or if that's correct and everything is in top shape maybe..stop gunning it at green lights? If all else is good, driving style is still important. I found mine got better when I was more chill with the pedals.

dave1123

Here's something. I have the 4.0 and 242. I doesn't really seem to matter weither I drive in 4 full time or 2wd, the mileage is about the same either way. It does matter if I'm loaded or not and how judicious I am with the go pedal. I get around 12 to 16 in normal city/suburban driving depending on weather and air temps and about 24 to 26 over the road at 65 mph. I'm geared at 3.55 with no lockup and 216K miles on it. I did switch to 4-hole Bosch injectors and only noticed a smoother low speed response. You've got to remember you're driving 2 tons with 195 hp and the friction of 2 axles, powered or not.

Daverig

I drive at 30 mph and I don't gun it at the green light. What's Op?

Daverig

I was thinking of replacing the injectors.

GCWJ

"OP" = "Original Poster". Means you in this case.

You should be getting what Dave is, that's my root point. I'll defer to his expertise. My wife has the same Jeep he does (except hers is bone stock) and gets the same.

dave1123

The only mod mine has is the injectors and the reason I replaced them is the cases of 2 of the original Siemens were cracked. As I said, it didn't effect overall mileage at all, but made it smoother at low speed response.

Oh, and I have a "Clearwater" head on it to replace the cracked 0331.