Poor MPG, Lack-luster power
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Poor MPG, Lack-luster power
I have a 2001 Suburban 4x4 with 132k miles. Purchased about 4 yrs ago with 82k miles. The best mileage I can pull is 15 mpg on a perfect day and 10-12 mpg all around. It has a 5.3 liter with 4:10 gears. I have synthetic in diffs and trans.
It is really under-powered though. It needs a double shift to pass effectively, and that is rarely achievable. Plugs and wires are maybe a year old. It doesn't misfire or throw any codes, other than I have had to replace the EVAP canister 2x since owning.
Looking for advice to improve sub-par performance. If I am going to get bad mileage, I would like some horsepower to go with it. Of coarse everyone wants power with great MPG, but I hear other people claim excellent power while consistently achieving MPG in the upper teens to low 20s.
Do I need a 6.0 liter transplant and taller gears?
It is really under-powered though. It needs a double shift to pass effectively, and that is rarely achievable. Plugs and wires are maybe a year old. It doesn't misfire or throw any codes, other than I have had to replace the EVAP canister 2x since owning.
Looking for advice to improve sub-par performance. If I am going to get bad mileage, I would like some horsepower to go with it. Of coarse everyone wants power with great MPG, but I hear other people claim excellent power while consistently achieving MPG in the upper teens to low 20s.
Do I need a 6.0 liter transplant and taller gears?
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Joined: Aug 2013
Posts: 997
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From: SE MI
I have an 01, with 4.10 gears and the 5.3, and she has plenty of power. Mileage is about 14/15, regardless of city vs hwy driving. You're not going to get anywhere near 20 mpg with 4.10s.
Where are you located? If you're in Colorado, Utah, or some similarly-high altitude city you're going to have significantly less power, say ~20% less, making it more of a dog.
Assuming you're closer to sea level, I'd look at the fuel and air systems. Check/replace your air filter, MAF, run some Seafoam through the brake booster line and fuel tank. Fuel pump is also a known issue - at 132K, if you haven't already replaced your fuel pump, you probably will be soon. Mine died around 115K.
ETA: The truck has 189k on it now. When it had ~150k on it, we towed a 7,000-lb travel trailer out to Yellowstone, including over a 9600-ft pass, racking up 5500 miles in 2 1/2 weeks.
Where are you located? If you're in Colorado, Utah, or some similarly-high altitude city you're going to have significantly less power, say ~20% less, making it more of a dog.
Assuming you're closer to sea level, I'd look at the fuel and air systems. Check/replace your air filter, MAF, run some Seafoam through the brake booster line and fuel tank. Fuel pump is also a known issue - at 132K, if you haven't already replaced your fuel pump, you probably will be soon. Mine died around 115K.
ETA: The truck has 189k on it now. When it had ~150k on it, we towed a 7,000-lb travel trailer out to Yellowstone, including over a 9600-ft pass, racking up 5500 miles in 2 1/2 weeks.
Last edited by intheburbs; Mar 17, 2014 at 5:41 AM.
Thread Starter
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I am located in MN. The vehicle originally came from IL. No elevation issues here. How do I tell if the MAF is performing as it should? Air filter is fine.
I don't know how it compares to SeaFoam, but the GM dealer did run a fuel system cleaner of some sort through it. Didn't do any good.
Should I be looking at the injectors or throttle body?
I don't know how it compares to SeaFoam, but the GM dealer did run a fuel system cleaner of some sort through it. Didn't do any good.
Should I be looking at the injectors or throttle body?
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