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  1. #1

    Default mpg on 04 sierra

    hi, have a 04 sierra 1500 4x4 extended cab with the 5.3. notice the fuel mileage seems to go down in winter with heat on(14). seems if i turn off heat it
    gets a little better. in warm months it gets better mileage.(16)\, except when i use the ac. took 800 mile trip south mid november and averaged close to 19.
    plugs and wires (mallory) done about a year ago,new air filter 1 month ago. don't drive it hard, i keep my foot out of it as much as i can, but cold seems to make it worse. thanks, any help would be appreciated.
    dave

    p.s. any ideas on where to get some performance parts for engine(cam,lifters, comp.chip)

  2. #2
    Jr. Apprentice
    Join Date
    Dec 2013
    Location
    lake butler, fl.
    Posts
    13

    Default

    I have noticed the same affects with my 04 Silverado but I have noticed a decline in mpg's regardless of whether the heat is on or not. Summitracing.com has lots of good stuff for these trucks along with jegs racing and these are very popular motors so parts aren't stupid expensive.

  3. #3

    Default

    hi thanks for your reply,yep, summit and jegs, but is the block ls1,ls2,ls3????? or something else. heard them refered to 327 because actual c.i. is 323. strong engine
    thanks
    dave

  4. #4
    Jr. Engineer BRB46's Avatar
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    Apr 2011
    Location
    Western Mass
    Posts
    209

    Default

    My mileage also drops in the colder months but I figured it was the winter blend gas. I don't know if it has anything to do with heat being on. A/C will have an effect on mileage.
    2006 Silverado 1500 5.3L ecsb Z71,afe pro s dry air filter, color matched tailgate handle and bezel,color matched front bow tie, led interior illumination, 5000K HID lows, Black powder coated wheels, Blacked out body side moldings, Rough Country 2.5" level/lift kit, Magnaflow muffler

  5. #5
    Legend
    TRPLXL2's Avatar
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    Jan 2009
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    Norwalk, Ohio
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    3,368
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    Default

    Your engine is technically an lm7 or lm33
    Ls1 is a 5.7
    ls2 is a 6.0
    ls3 is a 6.2

    I bought all my performance goodies at summit racing
    2004 Chevy Colorado
    LS1 5.7 swap/TBSS rear axle swap

  6. #6

    Default

    ok, thanks for the info. kinda thought L something, what's the difference between the Lm7 and Lm33 ?
    thanks
    dave

  7. #7

    Default

    Quote Originally Posted by dave13net View Post
    ok, thanks for the info. kinda thought L something, what's the difference between the Lm7 and Lm33 ?
    thanks
    dave
    The is Difference is the LM7 is a Cast Iron Block W/ Aluminum Heads, and the L33 is a Aluminum Block and Heads.

    LM7.....The Vortec 5300 LM7 (VIN code 8th digit "T") was introduced in 1999, and can be considered the "garden variety" version of the Generation III 5.3 liter V8's. The 1999 LM7 engine produced 270 hp (201 kW) and 315 lbft (427 Nm), 2000-2003 engines made 285 hp (213 kW) and 325 lbft (441 Nm). The 2004-2007 engines made 295 hp (220 kW) and 335 lbft (454 Nm), it has a Cast Iron Block and Aluminum Heads.

    L33....The Vortec 5300 L33 (VIN code "B") is an Aluminum Block Version of the LM7, and was referred to as the Vortec 5300 HO in marketing materials. How ever it should be noted that the L33 uses a flat top piston from the 4.8L instead of the standard dish piston found in the LM7


    EDIT.....I would add that there are Now 10...5.3 Liter Vortec Engines.....LM7 / L59 / LM4/ L33 / LH6 / LY5 / LMG / LC9 / LH8, and the New 2014" L83 EcoTec 5.3 Liter.
    Last edited by 99'HEARTBEAT; 12-21-2013 at 09:49 PM. Reason: Added Infor.

    MIKE


    99"SILVERADO
    5.3 l 3.73 l G80
    BLACK BEAR CUSTOM TUNE
    SNUGTOP l COLORMATCH l KATZKIN










  8. #8

    Default

    thanks.. what about a cold air intake, always heard that they are worse because they suck in the hot air from the engine
    thanks,
    dave

  9. #9

    Default

    Quote Originally Posted by dave13net View Post
    thanks.. what about a cold air intake, always heard that they are worse because they suck in the hot air from the engine
    thanks,
    dave
    If you're getting hot air from the engine bay, it's not a cold air intake. The factory intake setup is cold air. It draws in air from the fender well, not the engine bay. The main problem with the factory intake setup is the intake tube between the filter housing and the throttle body. But changing it isn't going to give you any real MPG boost. You might get 1 MPG if you're extremely lucky with it.

  10. #10
    Sr. Mechanic
    Join Date
    Jun 2011
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    Tuscaloosa, AL
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    160

    Default

    There isn't really a one performance part under $800 that's going to give you huge gains in the HP, Torque, and MPG categories. You have to get a set up like a new intake tube/filter then maybe and exhaust and then a custom tune. When you put at least two of those three together you'll start seeing gains. I went with the intake tube/filter with a custom tune from BlackBear and they have helped a lot
    2004 GMC Sierra SLT 6.0L 4x4
    UWS Low Profile toolbox 10% tint front and over stock back tint
    AirAid MIT and K&N airfilter
    BlackBear Performance

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