ryan_prettyman

iTrader: (2)

I really need You guys help I just bought it last year, it has the flex fuel 5.3, as soon as I bought it, I lowered and put the silverado ss wheels with falken 275-55-20's on it and flowmaster supertruck exhauste system on it. the truck was bone stock for 2 weeks before I started modifying it. I have had v-8 chevy trucks my whole they usually do good on gas, this one is shitty I only got 260 miles to my 26 gallon tank this time and I am not even running flex fuel and my air fuel ratio runs 13.4 to 1 all the time! Please help before I sell it and I would like to know the miles you guys get to your tanks.

jaegmc99

Your A/F isn't bad. Your mileage isn't great for a new truck but how many miles are currently on the truck? I didn't pull full mileage out of some of my trucks till about 10-12k miles on the odometer.

shupe

iTrader: (7)

How many gallons did you fill your tank up with? Use the number of gallons used to fill up by miles driven to figure out your gas mileage. Using the tank size isn't beneficial unless you drive it until it is absolutely empty before figuring your mileage. I wouldn't rely on the DIC for accurate mieage either.


What makes you think your AFR is 13.4 to 1? Are you using a wideband 02 gauge? Either way if you are running 13.4 to 1, that WILL affect your mileage. Sensors, Tune, ect. might need to be checked out to correct AFR.

ryan_prettyman

iTrader: (2)

Well first of all I have a hyperpac and it told me that I am 13.4to 1 and the truck has 42,000 on it also, every one keeps telling me it is the wheels I just don't know and I just put 21 gallons in it and it has 260 miles to the tank and it was on empty, If I didn't sell the factory 17" wheels I would try putting them back on.

wastedrubber

iTrader: (10)

you got a 26 gallon tank? i get about 250 - 280 miles to a 23 gallon tank. but that's with 6L and substantially heavier truck.

old motorhead

iTrader: (10)

You're right. Your mileage sucks. Something's out of whack. The heavy wheels may be part of it. If your replacement wheel and tire combo is taller than stock, your mpg is better than indicated. You're actually going farther and faster than your speedo and odo are telling you. Check your speed with a hand held GPS. You might be surprised.

If your afr's are actually 13.4, that's the other part of it. My afr's run 14.5 to 15 on the truck in my sig unless it's under a load or accelerating. It's about 500rwhp and gets around 16mpg.

ryan_prettyman

iTrader: (2)

Well I had the speedo calibrated for tires with my hyperpac and how many miles do you get to a tank on your stepside, I gotta tell you I am really frustrated about this. What do you guys think the issue is?

ryan_prettyman

iTrader: (2)

MY book says I have 26 gallon tank but I have ran it on empty several times and I have never put more than 23, so what do think the problem is guys I am running out of ideas!

fastgmc53

iTrader: (33)

Try simple stuff like air filter and check the spark plugs and gap...... I get 280 to 310 to a tank depending on how I drive. I doubt you o2 sensors are fouled .... maybe try some fuel injector cleaner. Good Luck

GMCtrk

iTrader: (27)

My mileage recently went to ****, it's likely due to my exhaust leak, o2's pouring a ton of gas in.