Gas mileage on my truck.. UPDATE

[Down4U]

So I put my truck through the test to try and figure out her true gas mileage these days. Here's what I've come up with.

This is when I filled her up on the first of March. It took almost $33 (What I usually pay more or less), or almost 17 gallons of octane 93 out of a 23 gallon tank. I reset the trip odometer to zero as seen here.

Today, the seventh of March, I had to make a trip to the gas station again, since I had a quarter tank left. The trip odometer reading is seen here. I didn't have the camera with me today, but it came out to $33 even, or a little over 17 gallons at the pump (probably 17.010).

So if my math is right, the jeep having consumed about 17 gallons of gas over 198.8 miles worth of city driving, she rates roughly about 11.6 MPG. I guess that's not that off from the rated 15 MPG that Chrysler gives for my jeep, but still kinda sucks for a six cylinder engine rated for 185 hp at 4600 rpm.

I'm sure an engine with 113k miles on it like mine is prone to lose compression, and so it'll probably lose some of it's response and burn gas less efficiently. How do I help improve that?

 

[Eli]

is the 15mpg figure city or highway? You'll probably get at least 15mpg on the highway if you get 11 in the city.

 

[XMan]

Weird, my Durango has a 4.7L V8 and I average about 14-15MPG. Sure your engine doesn't need a tuneup?

 

[Down4U]

Originally posted by: Eli
is the 15mpg figure city or highway? You'll probably get at least 15mpg on the highway if you get 11 in the city.

15 MPG is city driving. I discussed highway driving on a different thread and calculated her burning 17 MPG for highway driving (100-mile highway drive roundtrip takes a quarter tank, quarter tank out of a 23-gallon tank for my truck means 5.75 gallons, so 100/5.75=17.4 MPG).

 

[Down4U]

Originally posted by: X-Man
Weird, my Durango has a 4.7L V8 and I average about 14-15MPG. Sure your engine doesn't need a tuneup?

I think she's due for one soon. I don't remember exactly when I had one done to her.

 

[XMan]

Yeah, definitely do plugs, plug wires, cap, rotor, all that jazz, if you haven't done it for a while.

 

[thomsbrain]

Don't expect to match the EPA numbers unless you drive so slowly that grandmas are passing you and shaking their fists.

 

[flood]

your MPG will also depend on how you drive your car.

 

[Down4U]

Originally posted by: thomsbrain
Don't expect to match the EPA numbers unless you drive so slowly that grandmas are passing you and shaking their fists.

That's another thing I figured.

 

[Down4U]

Originally posted by: flood
your MPG will also depend on how you drive your car.

I don't drive her aggressively. I may engage the over-drive one or two times if I need to, but otherwise I'm rather conservative.

 

[Down4U]

Originally posted by: X-Man
Yeah, definitely do plugs, plug wires, cap, rotor, all that jazz, if you haven't done it for a while.

Rotor? You mean what spins that rod inside the cap?

 

[etech]

Originally posted by: Down4U

Originally posted by: Eli
is the 15mpg figure city or highway? You'll probably get at least 15mpg on the highway if you get 11 in the city.

15 MPG is city driving. I discussed highway driving on a different thread and calculated her burning 17 MPG for highway driving (100-mile highway drive roundtrip takes a quarter tank, quarter tank out of a 23-gallon tank for my truck means 5.75 gallons, so 100/5.75=17.4 MPG).

You cannot estimate gas milage by reading the needle on the gas guage.

To add to the others good suggestions,

Check your tire pressure.

Keeps your revs under 2k as much as possible.

Change your air filter.

 

[XMan]

Originally posted by: Down4U

Originally posted by: X-Man
Yeah, definitely do plugs, plug wires, cap, rotor, all that jazz, if you haven't done it for a while.

Rotor? You mean what spins that rod inside the cap?

The thing on the tip of the rod. Pretty easy to change, most Chrysler products just have an allen head screw holding it on.

 

[Down4U]

Originally posted by: etech

Originally posted by: Down4U

Originally posted by: Eli
is the 15mpg figure city or highway? You'll probably get at least 15mpg on the highway if you get 11 in the city.

15 MPG is city driving. I discussed highway driving on a different thread and calculated her burning 17 MPG for highway driving (100-mile highway drive roundtrip takes a quarter tank, quarter tank out of a 23-gallon tank for my truck means 5.75 gallons, so 100/5.75=17.4 MPG).

You cannot estimate gas milage by reading the needle on the gas guage.

To add to the others good suggestions,

Check your tire pressure.

Keeps your revs under 2k as much as possible.

Change your air filter.

Originally posted by: Down4U
This is when I filled her up on the first of March. It took almost $33 (What I usually pay more or less), or almost 17 gallons of octane 93 out of a 23 gallon tank.

Tire pressure on tires is at 32 psi (I check every week).

Only time I can't help keeping it under 2k revs is when she's shifting from first to second. No matter how conservative I am with the gas pedal as it does that gear change, she never shifts to second until after maybe 2.5k RPM. The only time she doesn't wait that long is when I'm going along real slow, like about 10 MPH.

 

[Down4U]

Originally posted by: X-Man

Originally posted by: Down4U

Originally posted by: X-Man
Yeah, definitely do plugs, plug wires, cap, rotor, all that jazz, if you haven't done it for a while.

Rotor? You mean what spins that rod inside the cap?

The thing on the tip of the rod. Pretty easy to change, most Chrysler products just have an allen head screw holding it on.

Oh. I wouldn't typically tune her up myself, I take her to my mechanic. I just like to make sure they are changing wha they're supposed to. Yes, I do supervise them. 🙂

 

[Vette73]

Why are you using High Octane???

Most (like 90+%) run best using 87 Octane.

 

[isekii]

isn't premium gas for 10:1 or higher engines ?

mine requires 91 octane..

2JZ-GE 😉

 

[Vette73]

Originally posted by: isekii
isn't premium gas for 10:1 or higher engines ?

mine requires 91 octane..

2JZ-GE 😉

Its also depends on the heat in the Cyl., Timing, etc... So Comp. of the engine is just one thing.

So most cars and trucks run best off 87.

 

[LAUST]

Honeslty when it comes to engines (Trucks especially) I have never combine "Chrysler" with the word "efficiancy". I'm getting better milage then you out of a supercharged 5.3 with 4.10 gears and agressive tuning to boot. (15 city 19 hgwy, 13 with a 8000lb trailor on the back, single digits when I race though.. 10 injectors active then 😉)

 

[etech]

I missed that you are using 93 octane.

You really don't need that high of octane and are just wasting money by using it.

 

[Evadman]

Originally posted by: etech
I missed that you are using 93 octane.

You really don't need that high of octane and are just wasting money by using it.

you also get less mileage.

 

[PreDatoR]

what kind of a jeep is it? don't think i seen that part. My dad's 98 Wrangler with the 4.0 I6 gets 18-19 for him. Its also a 5 speed which helps somewhat. the super unleaded is a waste of money for that motor though. its probably only has 8.5:1 maybe 9:1 compression and it don't need the higher octane... I have a old chevy truck with a pontiac 389 V8 in it that is 10.5:1 and it needed 92 octane at the pump and 32oz of octane boost just so that it would run without knocking and pinging real bad. And that motor gets 12 mpg and had over 300 hp in it.

 

[Walleye]

what's your point? my truck gets 5 miles to the gallon towing a trailer, 7 on a good day when not towing a trailer.

btw, that's highway 😛

oh, and i have 2 tanks, a 20 gal original, and a 30 gal reserve where i used to have a spare tire.

I also live in SOuthern California, and typically pay the most in the nation for gas.

so, im hit hard by this gas crap.

 

[FelixDeCat]

Originally posted by: flood
your MPG will also depend on how you drive your car.

 

[WinkOsmosis]

Originally posted by: Down4U

Originally posted by: flood
your MPG will also depend on how you drive your car.

I don't drive her aggressively. I may engage the over-drive one or two times if I need to, but otherwise I'm rather conservative.

OH MY GOD. Overdrive is a gear. Not using it is why your mileage is so crappy.

How the hell can people not realize what overdrive is???