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Thread: po171 & po174

  1. #1

    Default po171 & po174

    I recently turboed my truck and its running like poop. i got a retune so far. but this is whats going on.... i cold start the truck and the AFR is 17-20 " lean" for almost a munite then it will level out. but if i put the truck in drive or reverse 1/2 the time it dies. if im crusing it will read between 14.5-15.5 AFR. but if i give it any boost and let out the AFR will go stright to 20 and the truck shutters alittle then it levels back out again. it also wants to die when i come to a stop. ive been trying to check for leaks and ive replaced the plugs, wires, during the swap. new hoses on the pcv valve. never touched anything ariound the intake manifoild. and the truck ran fine prior? ive also sprayed carb cleaner twice and havent found anything any ideas?

    - - - Updated - - -

    so far this is what i've checked.... Cleaned the MAF, made sure all the cold side piping was secure, replaced the pcv hoses, made sure the intake manifoild bolts were snug, made sure the o2 sensors were snug, installed new exhaust gasket. snug down the manifoild gaskets, then sprayed carb cleaner around everything. only thing i havent done.... tried a buddies MAF sensor, replaced intake gaskets... bout all i can think of and i got a retune on the way soon.... the truck ran fine before the swap and i didnt touch the intake at all? i did how ever change the rockers and springs. would a valve cover gasket mess with it? or even the oil dump tube mess with it?
    2004 gmc sierra ext z71 5.3
    KB racing hot pipes 3.5" : 76mm turbo: 4l80e : Circle-d 2b multi disk :Walbro 400 : Racetronix Hotwire kit : TB coolant bypass : Nelson 91 Pcm : Tr 220 Cam : Brian Tooley double springs kit : Ls7 Lifters : Stage 3 heads : Custom Intake Manifold :80lb Injectors : Ported TB : 40k tranny cooler: Plx dm-100 gauge: Auto meter fuel and boost gauge:
    Custom Speedo : Leveling kit :Smoked led taillights and 3rd break light : Black projectors and fogs with hids : Blacked out grille : 33's on 16's : Clarion flip screen: sound que 12" subs: clerion 6x9's : Memhpis amps: Alpine componet set.
    Future mods... Detriot tru-trac, deviels own stage 2 meth kit, MORE BOOST!!!!!!!!!!!!!!

  2. #2


    Since you have checked plenty of things I will bump to hopefully get others to respond.

    Could be as simple as needing the tune to compensate for the increased air of the turbo, after tune may need larger injectors.
    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

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