MPG too low? !?!

[puddle hunter]

Y'all are talking yourselves into confusion!!

Very simply put, you're all reading the TRUCKS FACTORY MANUAL... if you have a performance tune, or a supercharger, fuel consumption will change with octane levels. Your truck will run, it will just run "different".

89 performance tune + 89 octane = getting what the aftermarket parts provider describes
89 performance tune + 87 octane = not what the aftermarket parts provider described, including, but not limited to, poor gas mileage/performance. The same holds true for superchargers.
89 performance tune + 91 octane = "Warp speed Mr. Sulu!!"

As for the trucks built in MPG gauge...
If you're wanting to track your average MPG over the life of your tank, reset with the truck in park, at the time of fill-up...never reset until your next fill up. This is how the math works.
If you're wanting to track your current MPG (while cruising the fwy for example) reset all you want... just be aware this will reset your tank average as well.

 

[MTF]

Yup, there a whole mileage thread with lots of input never read any of them, because it doesn't pertain to me.

---------- Post added at 06:55 PM ---------- Previous post was at 06:53 PM ----------

But getting back on track here 6 mpg. is still not good.

Chris, I hope you find something to correct your situation.

 

[Evanscott29]

"But it's a little scary when the book tells you a little pinging or knocking is OK!"

Thats what she said!

 

[svtchris1021]

Very true! Puddle! I just gas up at shell with 89 ... Reset the gauge.. Made record on gas cuddy see how it goes

 

[MTF]

Even though I had a major brain fart with the octane thing, which I don't understand why anybody would put blend gas in these trucks but a lot do anyway.
Hell my lawn equipment never sees anything other than 93 octane. Too each his own.

I'd still like to help sort out your issue.
You have the scan tool, so why not use it and check your live data and rule out a couple of things.

I would check your AFR, this should be at or near 14 (+ or - .2) both commanded and actual.

Then look at your fuel trims both long and short, bank 1 and 2.
Shorts should always be trying to get to 0.0 on both banks equally as much as possible.

Longs should never be 25 (- or +) or higher.

Who knows maybe you did get a bad tank of gas, throw some injector cleaner in anyway.

You can also try a battery disconnect, this will force a new learning cycle.
Or load a different Tune.

That's about all I have to offer.

 

[svtchris1021]

Air fuel wise everything its cool.. Been tracking down the miles to E with the odometer and everything seems right :S odometer is getting the right miles from the miles to E maybe i guess was a bad tank of gas like you said.. Anyway ima try that injector cleaner.. Never used one before so i guess its time

Next tine ima switch 91 for sure.. But fown here in socal it almost 5 bucks a gal u.u'

 

[MTF]

Keep us updated

 

[bgs73]

Any updates?

Sent from my SCH-I545 using Tapatalk

 

[First Truck]

$85 for a dealer fuel injector cleaning? Really, my dealer wants close to $300 2 do a injector cleaning. R you quoting a dealer price directly? Me needs 2 know how much 2 beat up my dealer here in on the east coast.

 

[MTF]

Raptor Tax! LOL
I have no idea why it would be that high.