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Thread: ok new problem

  1. #1

    Default ok new problem

    so about 4 weeks ago i posted how my throttle body was backfirring and was loosing power. so with everyones advise i replaced the fuel pump and also did a tune up new plugs ,wires, cap , rotor,..

    now im haveing an idle issue when the truck is warm and is sitting at idle in park the rpms go up and down someimes low e-nuff to where it almost stalls.. and when you drive it it sputters like i have a dead hole. any advise would be great thanks jerry

  2. #2
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    stephan's Avatar
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    Could you remind us again what year, model, engine etc.
    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


  3. #3

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    The truck runs great when cold but not warm right? Check to make sure you don't have any vacuum leaks. Can spray starter fluid around intake/vacuum lines to see if it affects how the truck runs. Have you cleaned you IAC(Idle air control)? Any check engine lights/codes? Double check your plugs and wires to makesure nothing is amiss since you changed them. Sounds like maybe your IAT(Intake air temperature) sensor maybe reading wrong?

    Hope this helps

    2000 GMC Sierra 1500 Z71
    Stock 5.3L
    High Flow Filter
    Dual Exhaust
    KC Driving Lights behind Grille
    2011 17" GMC takeoffs
    Nerf Bars
    Toolbox

  4. #4

    Default

    Timing could be the issue.

    Need to be sure that the Timing connection to the Computer is disconnected when you set the timing on the Distributer.
    Pavement sucks... :grrrrrr:



    1994 K1500 4x4 Ext. Cab
    PCM chip and Xenon 8000k bulbs
    350cu.in bored over .050"
    balanced Crank, 10:1 compression
    Flat top pistons,cam,ported heads
    Option Racing Cold Air Intake
    Holley Throttle Body Spacer
    Accell Igition, 45kv coil
    FloTech Headers, no CATs, dual exhuast
    Goodyear Silent Armor A/T 305/70-16
    Pioneer SupertunerIII CD USB Bluetooth
    Kicker ZX200.2 ZX Amp
    Kicker Audio COMP 10" Subwoofer

  5. #5

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    sorry its a 90 suburban with a tbi 350..... no check engine lighs are on

  6. #6
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    stephan's Avatar
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    I gotta agree with Magna on the IAC valve for the erratic idle portion of your problem, plus EJ on checking setting the timing for your sputtering hesitation problem. You've done so many things here that you need to go back & check all the basics since you're not getting any codes. Also, when you did your tune up, did you check the compression? Low compression on one cyl. will make this thing a slug on acceleration, & also cause idle problems cuz the pcm can't keep up with what it's trying to tell the TBI & the distributor every time the low hole comes around in the fireing order.
    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


  7. #7
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    murdog94's Avatar
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    Im on board with the Idle air control valve.. there is no sensor for intake temp.
    Mike

    Currently

    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!!!!"

  8. #8

    Default

    If you still are running the stock intake manifold and TBI, there is a real good chance that the intake has accumilated alot of sludge.

    Once you remove the IAC, look into the bottom of the TBI, you should not see any discoloration. Otherwise it is time to remove the TBI and give it a good scrubbing.

    With the TBI off of the Intake look down inside, and see if there is any build up. That is a good time to clean all of that out also.

    Remeber to use TBI cleaner not carb cleaner.
    Pavement sucks... :grrrrrr:



    1994 K1500 4x4 Ext. Cab
    PCM chip and Xenon 8000k bulbs
    350cu.in bored over .050"
    balanced Crank, 10:1 compression
    Flat top pistons,cam,ported heads
    Option Racing Cold Air Intake
    Holley Throttle Body Spacer
    Accell Igition, 45kv coil
    FloTech Headers, no CATs, dual exhuast
    Goodyear Silent Armor A/T 305/70-16
    Pioneer SupertunerIII CD USB Bluetooth
    Kicker ZX200.2 ZX Amp
    Kicker Audio COMP 10" Subwoofer

  9. #9
    Sr. Apprentice Looey's Avatar
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    Aug 2009
    Location
    London, Ontario
    Posts
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    Default

    Double check that the spark plugs are the right ones. You did use AC delco's right?

  10. #10

    Default

    will check these things out this weekend , when it comes to timing i never touched it .. and as far as doing a compression test i never did one, but it accelerates fine just sputters a little bit like it has a mis

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