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1997 Chevrolet Suburban 1500 Question: Low idle and runs rough, plenty power, replaced egr,tps,iac fuel pump and filter

 

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Leu, 5.7L V8, Minot, ND, February 15, 2013, 13:40
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Replaced distributor, updated injectors, replaced o2 censors, runs much better but still idles at around 500 rpm and runs real rough. Also has a slight backfire when idling.

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  • Answer #1

    pushrod February 15, 2013, 17:59
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     Master

    Scope ignition, smoke test for vacuum leak, pay cloose attention to intake gaskets. Can use carb. spray but have fire
    extinguisher handy! INTAKE and plenum. Intake gasket vacuum leak can cause intake backfire. Is it exhaust backfire?
    Is CEL on? Any trouble codes?

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    Leu, February 16, 2013, 15:39
     Rookie

    It sounds like exhaust backfire and it sounds like lil pops in the cat. Could it be a clogged cat? I drove it today about 100 miles on highway and it runs smooth at 2000 rpms but slight struggle to accelerate. When I slow down off of highway it idles real,low and shut off once on me. It is giving a po300 random misfire code and the code for an o2 censor , could it be the knock sensor throwing the comp? It doesn't give me a code for the knock sensor though.

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