Question about 1998 GMC Sierra

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Flooding out. using lots of fuel. black smoke

98 z71 chev began skipping. changed plugs and wires and fuel filter. skip begins after the truck has run a few minutes. if you let it sit for an hour it will run fine for a short time. Seems to be loading up on fuel. Fuel milage is now terrible. Also has a gas smell but cannot find a leak. Computer shows intermitent cylinder misfire but no specifics. Thinking bad injector but my experience is limited.

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You could have a bad injector spider if the truck is vortec,if not look to the idle air control valve if this part is bad it won't get the right amount of air and flood the truck out, hints why you are smelling fuel, also look at to o2 sensor if this is bad the computer won't adjust the timing another reason you're smelling fuel . hope this helps you and good luck!

Posted on May 30, 2009

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I had the same problem,1998 z71 5.7 l r code engine, a buddy who is a mechanic said to replace the fuel rgulator,located under the top plenum(manifold)...same thing smells like gas and has intermittent miss fire ....replaced the part and runs great....$53 dollars at autozone plus $18 for upper plenum gasket kit....Fuel regulator will be leaking when you remove manifold and there will be gas on lower manifold.This is your problem.

Posted on Sep 16, 2009


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