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1995 Chevrolet Impala SS Question: my car starts idles ruff for about 30 seconds to a minute then smoothes out

 

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hbomb23, 5.7L V8, Union City, CA, June 11, 2013, 18:06
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 Rookie

added a fuel additive, changed o2 sensors, cleaned mass air flow sensors, runs really smooth except at start

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  • Answer #1

    Hal... (see my shops), June 11, 2013, 20:33
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     Master

    I would like to check fuel pressure and maybe volume. Get the datastream as well.

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  • Answer #2

    June 11, 2013, 21:17
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     Master

    You can try changing the fuel filter. A very dirty filter can disrupt flow and volume at start-up when they are starting to plug-up. You can also try cleaning the IAC (idle air control) to see if that helps.

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  • Answer #3

    Greg's Orange Auto (14262 Answers) , Orange, CA - (714) 361-9386
    globalhelper June 12, 2013, 06:15
     Master

    poss vac leak.do you have any eng codes if so post so we can adv

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  • Answer #4

    A+ Japanese Auto Repair Inc (35 Answers) , San Carlos, CA - (650) 204-3032
    Eric Sevim June 12, 2013, 10:18
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     Technician

    Cold start morning roughness that clears up... possible leaking injector (over night or if you let it sit for a while), possible head gasket issue (coolant leaking into cylinder), possible oil leaking past valve seals (hence oil fouled plug until it clears up.

    Check coolant level, has it dropped at all? Leaking fuel injector has to be tested with fuel pressure tested and some other stuff. The leaking valve seals... look at the exhaust, is there any coloration during the rough running? Black, white, blue? - Keep me in the look.

    Eric Sevim - Co-Owner - ASE Master Certified Technician
    http://www.aplusjapaneseautorepair.com/
    San Carlos, CA 650-595-2277

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