02 Misfire 5.3

[65GTO]

I have an 02 silverado 5.3, it has a miss at about 1200rpm underload. No check engine light. Fuel injectors were cleaned at precision tune. I replaced spark plugs. It has 60k miles. Also sometimes you can hear a fluctuation at idle. No problems starting in mornings here in NC.Could it still be intake gasket? Is the fel-pro gasket as good as OEM?

Thanks

[jro909]

did you do the wires? when its really cold and the truck has sat outside for awhile, if i let it idle i can feel what seems like a small miss...i too have new plugs and wires, i want to say it has to do with the ethanol in the fuel now a days..