MPG of a V8.. I know...

[doofenshmirtz]

UPDATE: Alright, so I originally pulled the pins and lubed them up. Pins came out and moved freely. What I did not do was check the pistons on the front caliper. Both had one piston froze up. Went to my local part slingers and got some A1 Cardone remans with a 2yr warranty at employee pricing and I will install them tomorrow. Hopefully this fixes, or well, improves the mileage I'm getting.

Appreciate y'all that recommended the calipers, and while it was my first thought and first check, I was not as thorough as I should've been.

I was going to say something about calipers as well, but saw you mentioned checking... My mileage was about 3-4 MPG lower when I had a seized caliper. The MPG readout went from 18s/19s to low 15s in the matter of a month.

The only other recommendation I have is that NAPA sells a pre-painted caliper with a lifetime warranty. I asked my local guy and he said if it seizes, we just swap the old with a new one, indefinitely.

 

[swanny]

We had codes thrown on 2 cylinders.

 

[swanny]

Driving style is a HUGE MPG factor in the V8. I get 16.5 - 19.5 with how I drive. My wife gets 12-14.

I drive like I’m trying to hypermile it, and she drives like she’s running from the cops.

Pretty sure this might be my problem, I know the wife stomps on it!

 

[hinmo24t]

All my new to me vehicles get the Seafoam love. Plugs are new OEM, and gapped proper.

The speed lowering won't happen. I-94 is basically Michigan's NASCAR speedway. 75 is the bare minimum otherwise you're fighting traffic or sitting behind a semi. 77/78 is about the average sitting in the median running radar.

I was gonna do a chalk test on the tires to see which PSI they like.

wild in a lifted SUV (not sure yours is, mine is) running around toward 80mph

i might in a euro car thats about it

 

[hinmo24t]

UPDATE: Alright, so I originally pulled the pins and lubed them up. Pins came out and moved freely. What I did not do was check the pistons on the front caliper. Both had one piston froze up. Went to my local part slingers and got some A1 Cardone remans with a 2yr warranty at employee pricing and I will install them tomorrow. Hopefully this fixes, or well, improves the mileage I'm getting.

Appreciate y'all that recommended the calipers, and while it was my first thought and first check, I was not as thorough as I should've been.

good luck, glad you found the culprit. i think i got some remans last time around and now a different wheel's caliper is frozen. the only thing i can say thats really ticking me off about this truck. other than that i love it

 

[ElDuck]

wild in a lifted SUV (not sure yours is, mine is) running around toward 80mph

i might in a euro car thats about it

Haha. I'll keep up with traffic in my 88 Comanche, lifted 4.5". 80 isn't scary. Pretty comfortable speed as long as everyone is playing ball and you don't have the people thinking they are traffic cops and holding down the fast lane at 68mph. Then things get interesting.

 

[eric merryfield]

Alright. Loving my 07 T4R Limited with the V8. The MPG is terrible. I drive 70 miles a day for work, 65miles of it being mostly flat highway @ 75mph. I was hand calculating my average at 13-14.5mpg. 105k miles.

Specs:
-Stock size, basic Goodyear Assurance A/T's @32psi
-105k miles.
-No lift

Replaced/new/added with no changes:
-All fresh Amsoil synthetics, front to back; Diffs, trans, t-case, motor, p/s...
-Front only steel RCI skid plate.
-OEM plugs
-OEM timing belt and water pump
-Serp belt
-Filter box mod to get rid of that second filter thing.
-Cleaned MAF
-Checked calipers for sticking.
-No codes
-Runs good,

I've got 265/70r17's and FJ springs for it, but they aren't on yet. DT midpipes and Borla catback waiting as well.

I'm not expecting 20's, but 14 is getting old..

Is there something else I'm missing, like a bad upstream 02 sensor that isn't throwing a code?

Appreciate it guys.

I am a original 08 v8 runner owner. 184K now.

Best mpg ever was with original factory tires, cruise at 78 from Indy to Mass 22.5
computer.....best towing a 20 foot trailer 14.7 from bristol Tn to MA with a challenger DP race car in 2010, yes original tires.

When the front wheel bearing were dying, I figured it out when it got better MPG towing a 20 foot open featherlite trailer with my dakota on it than empty...also from indy and back to Ma. in 2015

Suggestions: Suspect drag of some kind before you jump into motor. ie calipers, and bearings.

A scangauge and a thermal gun will tell you just about everything you need to know, ie tire temp, etc. Don't neglect that tranny fluid.

Under 2k in OD on the highway is the sweet spot for towing, and unloaded mpg

Currently it has a URD cat back exhaust on it(original broke in half towing 10K up 64 in VA) this spring and the free flowing is good for MPG and enjoyment

My truck is likely the only one that has competed at national drag racing events, and in 08 it ran a bone stock best of 15.18, this fall it was a bit slower at 15.38, but there a bit of junk in it and the weather wasn't as nice as in the 08 national at Epping......not to mention 175K miles of use....

Constants: Factory air filter, mobil one factory oil filter, mobil Diff fluids trans case etc. Tire pressure.....I max em out based on the tire.

Also for those in the snow belt, if it snows run it through the touchless carwash ASAP, never a seized caliper here, just saying and that road salt crap is frame death

What will a Y pipe and LT headers yield? TBD.

I can get over 20 on the highway as is currently. commuting 18-19ish, drive it hard subtract 3-4

Eric