I have a 2000 Silverado 4x4 w/5.3 with 58000 miles. I am getting
misfire readings on my scanner for cylinder 1,3,4 and 6. Cylinder
three sets right away. I have checked injector pulse w/ noid light and
stethoscope. I have checked grounds, checked fuel pressure is
51-52 psi with KOEO. The troubleshooter said it should be 55-62.
Could this cause it? I have also changed out fuel filter and swapped
coils and plugs.
misfire readings on my scanner for cylinder 1,3,4 and 6. Cylinder
three sets right away. I have checked injector pulse w/ noid light and
stethoscope. I have checked grounds, checked fuel pressure is
51-52 psi with KOEO. The troubleshooter said it should be 55-62.
Could this cause it? I have also changed out fuel filter and swapped
coils and plugs.
Answer: It's nice to hear from someone that actually does some
diagnosis on their own! The fuel pressure reading is a tad bit low, but
that probably wouldn't cause your misfire concern. The injectors
should be ok as well, unless they are clogged, but a quick can of fuel
injector cleaner can take care of that. I would be willing to bet that
your problem is a leaking intake gasket. Over time the seals on the
gasket flatten out and allow the intake to basically 'suck' air. This
added air causes a misfire condition, usually on the middle cylinders
like you have stated. An easy way to check this is to take a can of
brake clean, or carb spray (something flammable), and lightly spray
around the intake ports on each cylinder head while the vehicle is
running, and monitoring the idle. It should raise up when you spray
around the area with the leaks. This is best watched on a scanner,
which it sounds like you have one. The oxygen sensor readings will
also change, as will the fuel trim. If you find this to be the problem,
changing the intake gasket set is not a very difficult job on those
engines.
diagnosis on their own! The fuel pressure reading is a tad bit low, but
that probably wouldn't cause your misfire concern. The injectors
should be ok as well, unless they are clogged, but a quick can of fuel
injector cleaner can take care of that. I would be willing to bet that
your problem is a leaking intake gasket. Over time the seals on the
gasket flatten out and allow the intake to basically 'suck' air. This
added air causes a misfire condition, usually on the middle cylinders
like you have stated. An easy way to check this is to take a can of
brake clean, or carb spray (something flammable), and lightly spray
around the intake ports on each cylinder head while the vehicle is
running, and monitoring the idle. It should raise up when you spray
around the area with the leaks. This is best watched on a scanner,
which it sounds like you have one. The oxygen sensor readings will
also change, as will the fuel trim. If you find this to be the problem,
changing the intake gasket set is not a very difficult job on those
engines.
Chevy Silverado Engine Missfire
