fuel issues

Discussion in 'Chevy Silverado Forum (GMC Sierra)' started by nabisco_12, Jan 10, 2013.

  1. nabisco_12

    nabisco_12 Member

    04 z71 4x4 1500

    my truck is sucking fuel and not sure y. could the 4wd have stayed on even if it is off( just drove a few days with it on) i have a leak on my firewall on the radiator line im thinking it could of got a coil pack... or whatever it is. checked the air filter and looks brand new lol... before i start to throw parts at it any ideas? my fuel milage has been around 14 not it is 13-12 ish. it started to jerk on mt but the fuel was real low getting in town, fuel light was on said i had bout 23 miles left... only other thing is i moved my big ladder over some toward the middle but i wouldnt think that would cause it....
     
    Last edited: Jan 10, 2013
  2. buckmeister2

    buckmeister2 Member 2 Years 100 Posts

    We can certainly rule out the ladder...hahaha. You might have dodged a bullet when the fuel ran low, or you might have damaged the in-tank fuel pump. The internal fuel pump cannot survive when it is starved for fuel, and running way down like that usually wipes it out ($750 at the dealer), but can also damage the seals. Another cause could be reformulated fuel, which is place in almost all states, somewhere between 10/1 and 12/1, depending on your weather. There are several "winter formula" additives and treatments needed to satisfy the EPA, every one of which has been shown to reduce octane, and lower economy. My 01 1500 LT 4x4 5.3 is getting 13.7 around town, when I know it will usually get 15 or a bit better in warm weather (Heck, in Vegas, we don't need the winter crap, but they make them switch it, anyway). As for 4x4 constantly on...find some snow or dirt, and do some modest off-line burnouts with it in and out of 4x4. You will very quickly know if your 4x4 is actuated....yeeee-haw...
     

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