Results 1 to 10 of 12
Thread: Poor MPG. New plugs, wires next?
08-27-2013, 09:23 PM #1
Poor MPG. New plugs, wires next?
My Avalanche has been averaging around 12 MPG per tank. It's 4x4 with 3.73s, stock ride height, with Diablo 87 octane tune, and a K&N CAI. I made sure I reset the computer by disconnecting the battery after I installed the CAI. Anyways, last weekend I decided to clean the MAF sensor and change out my plugs. These were the stock plugs with 70k miles on them. I replaced them with Denso Platinum TTs (PT16TT) because I figured I'd trying something different. Next might be wires if my mileage doesn't improve much. Any other ideas? Also, what do you think of the plugs below?
-2008 Chevrolet Avalanche LT 4x4 w/ Diablo inTune 87 Octane, K&N CAI
-2012 Kia Soul !
-2003 Kawasaki Ninja ZX-6R 636
08-27-2013, 10:06 PM #2
Are you throwing any codes?
If at first you don't succeed, chances are, you are using too small of a cheater bar
1999 GMC Sierra SLT Z71 | 5.3 Vortec | Spectre Cold Air Intake | TransDapt TBS | Hypertech 30005 Tune | 2005 Chevy Tails | Denali headlights | AWS Bug Shield | 265/75/16 Mastercraft Courser A/T | "Ghetto" painted tailgate | Boss HD Speakers | 2005 Overhead Console | Dual Thrush Turbo Mufflers
Bigger Amp Alternator | Electric Fans | Oil/Trans Fluid cooler | Re-done exhaust | Paint | Interior Restoration/upgrade with newer model stuff | Window Visors (In channel) | Tint | Low-Profile Tool Box | LEDs throughout stock cab locations | And whatever is spurr of the moment
US Navy Sailor :sign0011:
08-27-2013, 11:15 PM #3
08-27-2013, 11:27 PM #4
Yeah. Mine looked like that after 40,000. But my knock sensors need to be replaced. You don't drive like a bat out of hell I'd assume. Does it have the 5.3 or 4.8?
08-28-2013, 12:46 AM #5
I don't think those plugs look that bad. Other than changing plugs, modern engines don't require much of a "tune up" like they used to. Change the plugs and fuel filter, clean the air filter and keep the tires aired up (go a little above the recommended air pressure on the door, maybe 5 to 10 pounds) and you should be getting most out of your fuel mileage.Clint (TX) 2001 Silverado LS 4.8L auto 2wd ECSB [GARAGE]
Gasoline or gunpowder: If you ain't burning one, you ain't having fun!
NRA Endowment Member 5 24 48 88 - Hendrick Motorsports FTW!
08-28-2013, 03:43 PM #6
08-28-2013, 04:33 PM #7
The plug wires on the 5.3L V8 engines are really short, so they are really easy to replace. I don't know how much they cost, but it can't be that much.
2013 Silverado LTZ White Diamond Crew Cab
Advent OGM1 Navigation
Husky Liners GearBox Underseat Storage
EGR Rail Caps
K&N Air Filter
Flowsound 40 Muffler
Hypertech Max Energy Tune (only top end limiter removed and AFM disabled)
Chrome Tailgate Handle Cover
TonnoPro HF-155 Tonneau Cover
WeatherTech Front and Rear Splash Guards
Husky Liners X-Act Contour Floor Liners
WeatherTech Side Window Deflectors
08-28-2013, 07:09 PM #8
That might be the next thing to do after I take it to the dealer. It's under warranty and I want them to see if there are any recalls or TSBs applicable to it and see if they can find anything wrong with the vehicle and fix it then.
08-28-2013, 07:38 PM #9
Fresh O2 sensors (front ones) might help. I like to change mine when the plugs are changed.
But, the thing that impacts mileage is rolling resistance. Tire pressure, thread pattern, rubber compound, alignment. tight brake pads.
Anything that increases the amount of power required to roll the vehicle will cut into the mpg.Ray
'09 Avalanche LTZ - Black
'05 Envoy XL (sold)
08-28-2013, 08:36 PM #10