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Bob_Vaughn's avatar
Bob_Vaughn
Explorer
Dec 25, 2013

Instant MPG

I recently purchased a 2013 GMC 3500 diesel truck and on the dic it will give me average MPG and the owners manual states that instant mpg is available if so equipped. My question is is it a software or hardware issue and is it something I could have the GMC dealer add? I wish the mfg. would make a manual that matched the vehicle that you purchase with just what is on the vehicle in the manual....

21 Replies

  • Regardless of what the manual says only average MPG is available. No option to add instant. You do get somewhat of an instant MPG for a few seconds after each reset.

    On Some trucks the avg MPG is accurate but most of the time they read high because the computer assumes less fuel has been consumed than actual. I am always able to add more fuel to my truck 1-1.5gal than the computer says has been used since last fillup. You need to compare hand calculated values to the computer readout for a few tanks to get an idea of how accurate yours is.