Truck is Getting Horrible MPG

[barrrf]

O2 sensor(s)...........

 

[Fogle]

my 05 with 5.3 and 4.11 crew got close to 16 stock in town. now leveled with 20s and 33s im at 13 with cam and tune

 

[Bootstrap]

I still get pure gasoline. :bishplz:

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[Ginger]

only pure gas i get has lead so i cant put it in......stupid cats

 

[Bootstrap]

You can choose 100% or 10% ethanol at like every station hete.

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[ScottyBoy]

You can choose 100% or 10% ethanol at like every station hete.

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Not here, or anywhere I have driven in the past two years. That would include all of Louisiana, parts of Texas,and Mississippi, and Alabama. Up until about two years ago, there was still one Mom and Pop service station (I say service station cuz they actually have full service and two Mechanic bays) that still had it but it was normally 15-20 cents more a gallon. Well worth it in my book. But I was super pissed when one day I drove way over there to fill up and I saw brand new stickers on all the pumps saying "May contain up to %10 Ethanol".

 

[Hunter.]

Still, seems normal to me. Maybe a tune would help you., data log?

I've read mixed reviews on results of MPG change after tune :shrug:, what's a data log?

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tune would help.


I personally HATE seafoam, caused more problems then help on a few of my trucks.

make sure your tires are properly inflated. any CEL at all?

you should be getting around 13-16 atleast, i get around 14-18 on mine

No CEL, 40 psi in tires. Opinions on tune?

I consistently get about 11-12 in town and 15-17 on the hwy. But I drive a heavy ass Suburban too. I have 3.73's and I also have NNBS Sierra 17's with AT tires. Stock height, but front torsion bars are cranked about 3/4-1inch.
I remember back when gas stations sold pure
gasoline with NO Ethanol, I used to average 14-15 in the city and 18-19 on the highway.

Mad dad's 04' identicle to this one would get 15 running 80, seems low to me :imo.

O2 sensor(s)...........

Would throw a code?

 

[Tylers88]

Did you get it aligned after you rebuilt it, I sure that being off wouldn't help mileage and with it being a prior wrecked truck I would get it checked anyway. Basic tune up stuff couldn't hurt either if it has some miles on it and it hasn't been done yet or for a while.

 

[BOO5TED]

My Silvy with the 5.3, Whipple, 4.11s and 305/50-20s gets the same mileage. That's seems REALLY low to me too. Here in Slidell there are only 3 stations left that sell pure gasoline, they are around .75 more expensive than everyone else though. issed:

 

[Ginger]

i wonder, i heard the signs of a fuel pump issue is bad mileage too isnt it? i wonder if in the wreck something didnt get messed up in the pump.

 

[slicksierra]

I had a pump go out 2 summers ago, no bad mileage before pump quit :shrug:

 

[Manbearpig]

2004 5.3 Z71 is getting horrible MPG, no SES light, new acdelco plugs like 150 miles ago, 40 psi on stock size tires, I'm getting 10 city, 13 hwy, hand calculated driving with 2k shifts. Truck had a bullydog on it before I believe, could it be set on a 93 or 89 octane tune or something? Cats clogged?

Mine gets that mileage with stock sized tires and thats it

:lol:

 

[D1nman]

hmmmm according to gauges i get 3-8 taking off lol but crusing about 50 i get like 16-18

 

[Hunter.]

Mine gets that mileage with stock sized tires and thats it

:lol:

You have 1500hd quadrasteer though?

I had a pump go out 2 summers ago, no bad mileage before pump quit :shrug:

I didn't notice a difference right before my Zr2's pump went out.

i wonder, i heard the signs of a fuel pump issue is bad mileage too isnt it? i wonder if in the wreck something didnt get messed up in the pump.

Not sure, when mine went out in the Zr2 I didn't notice a huge difference.

My Silvy with the 5.3, Whipple, 4.11s and 305/50-20s gets the same mileage. That's seems REALLY low to me too. Here in Slidell there are only 3 stations left that sell pure gasoline, they are around .75 more expensive than everyone else though. issed:

Here in NC we have these GO GAS stations that sell 93 octane non ethanol at the same pump as ethanol gas, they sell it a lot cheaper than other places too.

Did you get it aligned after you rebuilt it, I sure that being off wouldn't help mileage and with it being a prior wrecked truck I would get it checked anyway. Basic tune up stuff couldn't hurt either if it has some miles on it and it hasn't been done yet or for a while.

Alignment place said it was good. I put new acdelcos in it while I had it torn down, its got Mobil 1 synthetic in the engine and the diffs and I am putting a K&N drop in in tommorow.

hmmmm according to gauges i get 3-8 taking off lol but crusing about 50 i get like 16-18

Computer said 16.4 tonight going about 50 mph. Shop said the timing was off, would that cause any difference in fuel mileage?