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1990 GMC Jimmy Question: trottle body backfires and loseses pressure and cuts off

 

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ronjbird, 5.7L V8, Detroit, MI, September 30, 2009, 21:38
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my 1988 gmc jimmy backfires through the throttle body and looses pressure when driving , and cuts off. can anyone help me?

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  • Answer #1

    October 01, 2009, 07:14
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     Master

    is the check engine light flashing ? if it is count the flashes write then down those are your codes then you can take it from there.

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  • Answer #2

    Visitor, October 24, 2010, 17:04

    Had the same problem with my 1990. Check ur distributor cap and button.One or the other might be bad.

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    Visitor, June 02, 2011, 16:23

    i just put a new cap, button, wires, plugs, fulfiller, EGR, and cat. what can it be

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    Tj1988, March 07, 2012, 11:48
     Rookie

    My 88 jimmy is currently in the shop now for the same thing. The exhaust valve seats were bad but that didn't fix it 100%... But there was some broken grounds... If u figure it out I would lik to know what it was

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    Douglas Mazur, March 08, 2012, 14:26
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    remoove valve covers.Cech valve hieght.If rocker to loose on exhaust when intake opens the cylinder pressure release through intake causing backfire through throttle body.Seen this many times Doug dkmazur@telus.net

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  • Answer #3

    March 08, 2012, 14:15
     Rookie

    Pull valve covers.Jimmy is good for broken rocker [real cheap to repair] push rod comes partially through causing exhaust valve to not vent. On intake when intake valve opens pressure releases through intake.Seen this often

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