Question about 1999 GMC Suburban

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How do i find a large miss in my 1999 gmc suburban?

I have a dead miss in two cylinders in my 1999 GMC suburban, Ive replaced the fuel pump,spiderinjector with new plentum gasket on upper plentum also replaced the fuel pump 52psiat gauge. Ive changed the plugs today it runs a little smoother but still mssing through complete range.I plan on changing wire set tomorrow.any suggestings?

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  • Russell j B Apr 22, 2013

    thanks guy for all the comments there helpful.Ive since replaced the plug wires and coil wires and the distributor cap runs better,but still has miss.I took it to Autozone to get codes in came back random misfires then second trip came up with missfire on cylinder 1 . Got home to check compression and found brand new plug in #1 cylinder was completely black ,it's burning rich i guess just cant figure out why.the compression on cyl.#1 is 190psi on#3 is 160psi and #5is 170psi.all good and all holding .anybody got any ideas?

  • Russell j B Apr 22, 2013

    i've replaced plug wires coil wire,plugs,and distributor cap (not rotor)also had codes pulled at autozone came back missfire on cylinder #1 when i pulled new plug to check compression(185psi)the plug was black from burning rich .anyone with a clue i geuss a vacumn check is next i don't have any other problems with other cylinders


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Check the firing order for starters as 2 crossed wires give a symptom similar to yours. Have the fault codes read first as that can save you real money in finding the fault. Have a compression check done to eliminate a blown gasket between cylinders.

Posted on Apr 21, 2013

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SOURCE: misfire #4 cylinder 1999 gmc sierra 5.7 lt

Are you talking about the check engine light? If so it needs to be reset with a code reader. then if it re illuminates you still have an issue.

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SOURCE: I have 96 gmc 350 vortec. missing really bad. Ive

ou need to check compression on all the cly. do you know which cly is dead?

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SOURCE: 1999 GMC Suburban Wont Turn Over

It sounds like you have a security problem, I had the same thing it would fire and run for half of a second and then that was it if anything at all. Had the security system rebooted, now it starts and runs fine.

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SOURCE: 1990 GMC Sierra lifters knocking. Oil pressure

I doubt it....It could be a totally worn out engine.

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SOURCE: 92 GMC Jimmy Replaced fuel pressure and fuel

if you say you replaced the fuel pressure ? "regulator or pump" that was not very clear as to which so i am guessing and the filter but have no fuel to the fuel bar valve either you have no power to the pump or a clogged fuel line or a blown fuse or a short in the power suppluy to the fuel pump if you turn the key to on position without cranking it do you hear a slight humming noise if so the fuel pump is working ..if you do now hear this chances are as i stated above
the use of a test light is required to check for power to the pump as wel do you smell any gas =fuel lines are rotted .let ne know what you discover and check all your fuses

Posted on Dec 17, 2009

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