[Splash]

Hi all!
New to this forum as a member, but have read through many posts in here before...
I have a 07 GMC Sierra 1500 NBS(non classic)
Its crew cab 5.3L 2wd 216K
I havent had the truck long, but im amazed at how bad it is on gas!
Just did 1 full tank and only got 274 kms on the tank. Its a 99 litre fuel tank.
(Sorry i realize alot of the members are American, im not sure what the conversion is for miles)
Truck runs great, no lights on the dash, no miss or hesitation, no lack of power, and no fuel leaks!
Bought the truck this summer, tore it apart and did a full body and paint on it, and replaced fuel pump because it was leaking on the top portion of the sending unit.
Im not sure where to start with it, being no check eng light... atleast if it was on, id have a starting point or a reason to say, Ahh thats why it using so much gas! Lol
Ive talked to a few others with similiar trucks and im hearing 480 - 550kms are what guys are averaging to a tank of fuel...
Can anyone here chime in on why im getting such bad mileage?

 

[squatchy]

If giving it shorthand it’s a nnbs not and nbs. Any towing? How much warm up time are you giving it? City? Highway?

 

[xPosTech]

Go ahead and read the codes. Some of them don't set the SES light.

Ted

 

[RayVoy]

New plugs
New front O2 sensors
Synthetic oil in engine
Synthetic gear oil in diff
Clean throttle body
Disconnect battery (while cleaning TB) to be reset the PCM
Air tires a few lbs (30KPA) over door sticker
Check front end alignment
Remove dead weight (tool box, etc)

 

[Splash]

If giving it shorthand it’s a nnbs not and nbs. Any towing? How much warm up time are you giving it? City? Highway?

Yes, NNBS... Tried to go back and edit my post but i coudnt figure out how...
Lol
I have remote start and its beenn fairly cold here, so it idles a good 5 mins or more... No towing as of yet. Mostly city, with a few hwy kms,but not many at all...

 

[Splash]

Go ahead and read the codes. Some of them don't set the SES light.

Ted

Thanks Ted, i will try that! Really was at a loss with not seeing the SES light illuminated!

 

[Splash]

New plugs
New front O2 sensors
Synthetic oil in engine
Synthetic gear oil in diff
Clean throttle body
Disconnect battery (while cleaning TB) to be reset the PCM
Air tires a few lbs (30KPA) over door sticker
Check front end alignment
Remove dead weight (tool box, etc)

I am running synthetic 5W30, not sure about rear axle, as ive only owned the truck for a matter of months...
I never thought about plugs and O2 sensors, as the truck runs so smooth...
Front end has all been done since i bought the truck, and it literally drives itself down the road...
No dead weight in the truck what so ever as of yet...
Il try cleaning the throttle body, and a buddy of mine today just told me to try cleaning the MAFS. He says that could be dirty causing it improper readings...

 

[xPosTech]

When cleaning the throttle body yoy need to command it open rather than forcing it open by hand. Turn key on but don't start. I use a telescoping squeegee handle from front seat to hold accelerator to the floor. Use TB cleaner and MAF cleaner for the MAF. Walmart has a two can kit for reasonable cost.

Disconnect battery while cleaning MAF to zero out learned tuning offsets. When finished at first start up the engine will go to a high idle and then come back down to normal in several steps. Drive the truck and enjoy higher mpg and smoother idling.

Ted

 

[Splash]

When cleaning the throttle body yoy need to command it open rather than forcing it open by hand. Turn key on but don't start. I use a telescoping squeegee handle from front seat to hold accelerator to the floor. Use TB cleaner and MAF cleaner for the MAF. Walmart has a two can kit for reasonable cost.

Disconnect battery while cleaning MAF to zero out learned tuning offsets. When finished at first start up the engine will go to a high idle and then come back down to normal in several steps. Drive the truck and enjoy higher mpg and smoother idling.

Ted

Thanks Ted, appreciate the info!
We're getting some pretty severe cold here, so as soon as i get a chance, i will try this out.
Do you think that there's more to it than just a couple little cleaning methods?
Seems like im getting only about half the mileage as others with the same trucks...
Also, im a pretty conservative driver...
The lead foot was left in the past...
Lol

 

[silverado002]

X2 on what Ted said about the TB since its electronic. Do not force an electronic TB open as it can destroy it. Also the O2's can cause a drop in fuel economy if they are dirty and lazy to switch.

 

[Splash]

X2 on what Ted said about the TB since its electronic. Do not force an electronic TB open as it can destroy it. Also the O2's can cause a drop in fuel economy if they are dirty and lazy to switch.

Yes, il definitely take care in cleaning it the proper way, with it being electronic.
Il have to get a scanner on it and see the values, make sure one or both 02s arent on their way out...

 

[silverado002]

I had a ZR1 corvette that only had 50K miles on it and the O2's were causing a high NOX reading due to dirt and they were lazy to switch. Dealership actually told me I needed new cats. Wanted 4K for new exhaust system as it was all one piece. LOL. Replaced the O2's and voila no problems and fuel mileage increased slightly if I kept my foot out of it.

 

[Splash]

I had a ZR1 corvette that only had 50K miles on it and the O2's were causing a high NOX reading due to dirt and they were lazy to switch. Dealership actually told me I needed new cats. Wanted 4K for new exhaust system as it was all one piece. LOL. Replaced the O2's and voila no problems and fuel mileage increased slightly if I kept my foot out of it.

Lol
Ya, no doubt its hard to keep your foot out of something like that!
Il definitely have a look at the 02 sensors, make sure they're working within spec...
Hopefully i can nip this in the butt, cause i feel like i should be getting a lot more mileage out of a tank of fuel!

 

[Flyinfool]

When I had remote start for those cold winter or hot summer days, I did notice a significant drop in gas mileage.
You did not say if your driving is mostly long distance highway trips or mostly short city trips? Remote start and short trips will really eat gas.

 

[Splash]

Mostly city driving...
But i talked to a guy with an almost identical truck, same intown driving, and hes getting about 500kms per tank (99litre)
Im only at 274kms on my last full tank...
Thats not even close to where i should be

 

[Splash]

If the conversion is right, im only getting about 170 miles per tank!

 

[xPosTech]

For a while I had fuel used per minute displayed on my Torque Pro auxiliary dashboard. On freezing mornings it sometimes would take 15 miles before the fuel used would get to "normal" levels. I've seen it using twice as much fuel until the engine finally got to operating temperature and stabilized. If most of your driving is in town and less than 20-30 minutes thats where your fuel is going.

Ted

 

[Splash]

For a while I had fuel used per minute displayed on my Torque Pro auxiliary dashboard. On freezing mornings it sometimes would take 15 miles before the fuel used would get to "normal" levels. I've seen it using twice as much fuel until the engine finally got to operating temperature and stabilized. If most of your driving is in town and less than 20-30 minutes thats where your fuel is going.

Ted

Wow, well thats me majority of the time. I dont do a ton of driving, mostly shorter trips...
What do you suggest, maybe let the truck warm up, closer to operating temps before driving?
But most people say excessive idling leads to poor fuel mileage

 

[xPosTech]

Try this method:

Just take care not to overheat it.

Ted

 

[Paladin]

Mostly city driving...
But i talked to a guy with an almost identical truck, same intown driving, and hes getting about 500kms per tank (99litre)
Im only at 274kms on my last full tank...
Thats not even close to where i should be

I find it somewhat difficult to believe the guy you talked to is getting 300+ miles with mostly city driving. That is what I would get with my 00 with a 4.8L engine on mostly highway. And my truck was very well maintained.

The only way I see him able to do this was if he was hypermiling severely.