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  1. #1

    Default Super Charger Assistance Request

    I recently installed a super charger (wynjammer) with a reprogrammed PCM on my 07 Sierra. I'm running the 4.3L with a 5 speed M/T. When I disengage the clutch with a cold engine (i.e. downshifting approaching a stop) the engine revs up 700-800 rpm's. After the engine reaches operating temp it settles down and runs fine. I've checked for vacumn leaks and everyhting is fine. Can any one share some information on what might be happening and if there is anything I can do about it. The company suggested that I let my truck idle until it warms up.

  2. #2
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    Just a shot in the dark here Goldie, but I think this might be a good thing & is/was (re)programed in the PCM. When manual trans fluid is cold it tends to make the syncros sluggish & you need the higher RPMs so the gears will mesh on the downshifts.
    1988 Chevy C-3500 2wd (no pic)
    350 c.i. 5.7 L Stock Block, 4 Bolt Mains
    L-31 Vortec Heads, Edelbrock Cam & Intake,
    Holley 650, Flowtech Headers, Magnaflow exh.
    Jet Trans 700R4, B&M Ratchet, 4:10 gears,
    3" susp. lift kit "shadetree"
    No rev limiter, No speed limiter lol


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