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2002 Nissan Xterra Question: need help with code#4 misfire&throttle positioner switch codes and poor running

 

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greenmtgreg, Brownsville, VT, February 07, 2013, 20:37
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I have replaced spark plugs,wires,cap,rotor,fuel&air filters.My friend purchased vehicle last week.It had #4 misfire code & knock sensor code.I replaced knock sensor and gaskets found no cracked vac lines but she still runs poorly @idle.I added Lucas fuel treatment and dry gas with 10 gallons 93 octane.I did a cylinder compression test on 4 it was 125 lbs.Is there any problems with wiring harness or injector problems?

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  • Answer #1

    pushrod February 07, 2013, 20:42
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    Engine size?? Also 125 psi aint a bunch but should fire the cylinder. Other comp. readings? Smooth out with slight throttle?

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    greenmtgreg, February 07, 2013, 21:36
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    3.3 i replaced the throttle postion switch also i didnt check comp on the other cyl it does smooth out with throttle do i need to change injector?

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    pushrod, February 08, 2013, 06:08
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    Compression readings for other cylinders would be very helpful. Or at least 2 & 6. The other two, front and back, of the one you checked.

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  • Answer #2

    Greg's Orange Auto (13199 Answers) , Orange, CA - (714) 361-9386
    globalhelper February 08, 2013, 06:15
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    code be $4 ign or inj circuit is bad. rec your seek help from your mech as to not waste time and money

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    greenmtgreg, February 08, 2013, 20:54
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    i pulled plenum again changed injector runs great no codes thanks

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