Extremely poor mpg's! Ideas please!

Extremely poor mpg's in my dads 2006 4.0 v6 at taco. 52k miles

He has been complaining about poor gas mileage for awhile so I decided to check it out. I filled it up and drove normally for the full tank and did the math. If the gauges are reading correctly the truck is only getting about 13-14 mpg's!

It has billies set at 2.5 and 265/70/17 duratracs. I know this affects mpg's but this seems a bit extreme. I've also noticed that the power seems a bit sluggish and when going down hill when the truck should be picking up speed based on momentum it seems like its being slowed by something.

Wondering if anyone on her has any ideas or suggestions on what could be causing this or possible solutions. Someone recommended a trans flush and trans filter service but I'm wondering if that could be it.

PLEASE HELP!!!! Thanks guys

 

Btw I have already checked the brakes and they are operating normally.

 

Those tire changes might effect MPG 1mpg if not calibrated correctly. Lift might take another due to wind resistance... I get 17.1 average mpg in my DCSB, so that's about where you would be at...

Check tire pressure with the chalk test. Baby the accelerator. Check MAF Sensor...may need to be cleaned. Air filter might need to be replaced.

Maybe diff fluid change...I'd guess that before tranny flush...especially with the 4x4.

 

If it feels as though its dragging (slowing without known cause) check the parking brake. I just did that exact fix on my buds ford yesterday. His gas mileage went to **** and he said it was slowing down excessively for no reason. I had him drive it over to me, first thing I did was walk back and feel the rear brakes and they were hot. The cable was looser than it should have been and thus got hung up when he released the pedal causing the brakes to drag.
Note* I have billies set at 0 with 886s now, front plate bumper, and canopy. Still getting about 17 depending on if my right foot is feeling heavy or not

 

He checks tire pressure religiously and the air filter was changed recently. Haven't checked maf or diff. I don't think it's the lift or tires I have friends with the same truck with 6" of lift and 35's that are getting better milage.

 

Yeah, thats why I would think MAF or Diff...

Are the Duratrac's Load range "D" or "E"? "E" are much heavier and will drop MPG...

 

With this, I would check a minimum of 3 tanks and take the average. Topping it off can make the difference of 14 mpg and 22mpg, depending on the pump. Didi you use the same exact pump and let it stop itself at full to get the most accurate reading...?

 

I'll try that tomorrow hitman. As far as the gas pump thing I didn't get that scientific about it... YET. I think I might have to though.

As far as the parking brake goes wouldn't I smell some kind of burning smell if the brake was engaged and I was driving with it that way? I would think even if it was just slightly grabbing there would be some kind of smell and or squealing.

 

Maybe it needs a tuneup? When's the last time the plugs were changed?

 

You also have to consider where you are driving. Around town 13-14 are about average, freeway 17-20

 

You *should* smell brakes if they are dragging. On my buds, you couldn't until you were right at the wheel. Stranger things have happened.

 

Agreed

 

The tires make the biggest difference based solely on the larger circumference. The larger wheel wont turn over as many times as a smaller one and the odometer will think you're getting worse mileage than you really are.

 

Not another MPG thread.

Those tires and lift affect it. Regular maintance. Synthetics. Premium gas. No AC.

I get about 19.5-20mpg avg.

 

My truck is an AC and not a DC, same Duratrac tires but 265/75/16, i use synthetics, Billies set at 1.75, 89 octane gas, new plugs, diff. and gear box fluids changed, aFe Pro Dry filter, 37K miles.........I only get 14.5 MPG. I blame it on the ethanol.

 

Plugs should be changed soon, same with the diff oil. That'll buy you at least 1-2 mpgs. Second it feels like it's dragging from negative compression in the engine. It's just the way it's built. Mine does it too.

3rd, your county might still be on winter gas. That'll get you another 1-3mpg. I know it did in mine.

Duratracs in that size shouldn't kill the mileage that much if at all.

 

If your dads truck is just running around town with no short freeway trips then his mileage is in the ball park.

 

Sounds like alot of you are saying these numbers could be par for the truck. If some of the suggestions don't solve anything it might be goodbye to the taco. Gas is $4.49 here in Hawaii and steadily going up.

Thank all of you for your input. I will try a few of these suggestions in hope that they will help. Aloha...

 

Also, go easier on the skinny pedal. Sounds easy but a lot of people don't realize driving habits can account for something retarded like 30-40% of poor fuel consumption.

 

It's true. The single best thing you can do to alter fuel consumption is to not drive like an ass hat.