Really Bad Gas Mileage

[Yuke07]

Try converting the mighty dolar to whatever currency they have over their, like 50 cents u.s. to them is 500.

 

[johnebgoode]

There is nothing wrong with your truck. I do nothing but stop and go driving and average 8.2 mpg.
As far as A/C on high affecting mileage.....as soon as you turn on the A/C it affects mileage. The position of the fan switch from low to high has no bearing. When you go into the A/C mode the belt is now dragging more because your turning the compressor clutch and pumping freon throughout the system. This slows the engine down and causes you to provide more fuel, by stepping on accelerator pedal, to attain same speed. Fan motor speed is irrelevant, other wise when you have heat on high it would cause drop in mpg also. :thumbsup:

 

[Tcwhite]

I don't know my Dad is having the same problem with his 07' suburban. He took his in because his car shuts off when he tries to start it up. That seemed to be the fuel pump. They are still working on the mpg problem. He is used to getting 18mpg with mixed city/hwy. Now he is getting like 11mpg and nothing has changed as to his driving habits. Wil let you guys know when the dealership figures it out.

 

[PaulC]

1,200 miles is far too early to assess fuel economy. That engine is not broken in and there is still a fair amount of friction between the engine's moving parts. I would be patient and wait until the engine has at least 8,000 - 9,000 miles on it before evaluating fuel economy.

 

[Norris83]

not too sure wat MPG im getting, I live in Kuwait and i've tuned my truck for the DOD to stay on longer.. I used to average 20-21L per 100km now I'm on 17l per 100KM.

IF you've tuned the truck and they switched of the COT Temp enrichment off, then you will always be in 8 cylinder mode.

Plus also keep in mind, when you keep the car idle, the DIC reads 99/L per 100kms on mine.. This adds to the total average which is kinda crazy as it gives off misleading information...

 

[SAUDILTZTAHOE]

Well took the truck to the dealer and they found what's wrong with it, it was bad fuel pump so they chaned it and WOW what i defernce the truck drive and responce way better than the day i bought it, now i am getting 16.3 MPG highway driving and 13.5 to 14.00 city.

Norris83 now i am getting 14G/100KM and befor i was getting 22G/100KM.

So i think i bought the truck with bad fuel pump.

 

[Norris83]

what were the symptoms of the bad fuel pump???? I keep hearing a high pitched noise standing outside the truck, i know that was how ppl would catch the NBS truck fuel pumps going bad....

 

[SAUDILTZTAHOE]

what were the symptoms of the bad fuel pump???? I keep hearing a high pitched noise standing outside the truck, i know that was how ppl would catch the NBS truck fuel pumps going bad....

Well it was CEL as a lean condition and was traced to a bad fuel pump.

 

[PMD GTO]

what were the symptoms of the bad fuel pump???? I keep hearing a high pitched noise standing outside the truck, i know that was how ppl would catch the NBS truck fuel pumps going bad....

Hmmm, I have a brand new 09 and I have been hearing a high pitched noise and my mileage is piss poor. 14mpg mostly highway.