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  1. #1

    Default Spark Plug Suggestions - 1998 GMC Sierra Z71.

    so.. it's about that time to do a tune up, was wondering what some good plugs would be, and any suggestions, obviously they all do the same thing, just the material used varies, anywayz, was looking at some E3 diamonds, but not sure if they are worth the hassle and wait of ordering them off line v.s. just getting the oem ac-delco's that auto zone has... any in put is appreciated..
    1998 Sierra Ext. Cab Z71
    Projector headlights
    Flow Master 40 Series Delta Flow w/ Dual Exhaust
    2" suspenion lift
    camo vynil trim
    camo Z71 decals
    soon to be new tires and rims, and possibly wheel spacers and
    throttle body spacer
    From Oklahoma, Currently in VA.... VA sucks by the way....

  2. #2


    The Vortec Engines Perform & Run better......with A/C Delco Plugs......And with Wires going either with A/C Delco or Aftermarket wires,both will do the job.....the E-3 Plugs are not worth the $$$....
    Last edited by 99'HEARTBEAT; 08-30-2010 at 03:52 PM. Reason: Added Infor.


    5.3 l 3.73 l G80

  3. #3


    x2 on the ac delco plugs. I am running Napa wires or you can get some Taylor wires from summitracing.
    2004 Silverado 2500 Crew Cab 4x4, AMSOIL EA air filter, Granatelli MAF sensor, Throttle body spacer, Magnaflow exhaust (true dual to 2 in 1 out muffler), 6" ProComp lift (add a leaf and 5" superlift rear block), Bilstein shocks, 35's (Cooper Disoverer ST) and 4.10 gears, Rhino Liner, EGRUSA fender Flares and widow visors, extended stainless steel brake lines, firestone airbags w/onboard air compressor, Pioneer Avic X940BT navigation, Accel backup camera.
    1960 Land Rover Series II 88
    2001 Pontiac Sunfire
    2013 Toyota Avalon Limited (Wife's Car)
    NRA Life Member

  4. #4


    X3 on the A/C Delco's. I run MSD wires from

  5. #5
    Sr. Apprentice 01BlackBeauty's Avatar
    Join Date
    Aug 2010
    Washington State


    I guess I'm the odd man out on this one. Michigan Tech's R&D department recently tested the E3 plugs and found the claims of more power and increased fuel mileage to be true. I replaced the AC Delco Platinum plugs I was running with the E3 plugs and picked up 1.5 mpg. Other benefits are a smoother idle and quicker acceleration (not as much pressure on the pedal to obtain same cruising speed). As far as not being worth the money...the AC Delco Platinum plugs were $6.49 ea and the E3 plugs were $5.99 ea. so they were actually cheaper.

    '01 Blazer LS 4X4
    K&N MSD Gibson

  6. #6
    murdog94's Avatar
    Join Date
    Feb 2008
    Cloquet, Minnesota, United States
    Blog Entries


    My buddy ran them in his 5.7L V-8 and he had a random cyl misfire, after about 10K miles. The plugs were fouled up and no longer working. We put in a set of AC delcos (i dont run platinum plugs because i would rather change my plugs more often) and the random cyl misfire was gone.


    1997 Chevy S-10 Blazer 4X4 with 330K miles and counting (Hunting rig).

    2009 Saturn Aura XE (wifes car)

    2011 F-150 Crew 4X4

    "Hold it to the floor till you see God.... Then Brake!!!!"

  7. #7
    Jr. Apprentice
    Join Date
    Sep 2010
    Inland Empire


    With 99.9% of my customers cars i run the factory plugs, my recommendation is ac delco. thats what you engine is designed to work with. Sometimes, the aftermarket plugs will preignite, run too hot, or cause other problems that arent worth the trouble.
    "if i had eight hours to chop down a tree, I would spend the first six sharpening the ax."-Abraham Lincoln

    Gary ASE certified master tech
    94 k1500 33" tires Hummer rims
    NINJA 600

  8. #8
    Sr. Mechanic
    kburb's Avatar
    Join Date
    May 2010
    Blythewood SC


    i have friends the run 1/8th mile race cars with 50k plus invested in chevy big blocks and the will ONLY run AC DELCO plugs.

    91 Suburban

    D44/14BFF w/Disc conv - Yukon 4:88's - Yukon Grizzly Lockers F/R -13" lift - DIY4x Shackle Flip - 37 ATZ on 18 MT Classics - Doug Thorley headers - Magnaflow - Holley Pro Jection Intake - Ultimate TBI mods - Hydroboost Brake Conversion - Hysteer-X Over Conversion.

    (Coming up - Fuel Injected 383 Stroker - Divorced NP205 - D60 - 40" tires)

  9. #9
    Legend Bigbomber's Avatar
    Join Date
    Feb 2010


    Just make sure that whatever plug you do decide on that you also replace your wires.
    [/SIGPIC]2009 Chevy Silverado LT 1500 EXT CAB 4X4 Vortec 4.8L SFI,K&N air filter,Weathertech Floor Liners ,Weathertech Stone/Bug Deflector, Line X Spray On Bedliner, TruXport Rollup Tonneau Cover, Molded Mudguards, Viper 5701 LE 2 way Security Alarm/Remote Starter, Xm Satelite Radio,BILSTEIN 5100 rear shocks,BILSTEIN 5100 front levelling shocks,READYLIFT 2" rear lift blocks,Goodyear Wrangler Territorys -265/70R 17"

  10. #10
    Master Mechanic clgoch187's Avatar
    Join Date
    Aug 2010
    Gettysburg, Pennsylvania, United States


    i just did the plugs on my 4.8 and the retarded ass kid at auto zone tried telling me that gm runs autolites from the factory, and since they didnt have any ngks or ac delco double platinums instock i took the delco iridiums and ive noticed that it feels like a have miss at idle after i run my truck for 30 min or so. any ideas?
    03 Silverado 1500
    285/75/16 BFG's
    2 Blaupunkt 10" vW1000 subs in Subthump box
    ProComp Level Lift & 3" rear blocks

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