08 Silverado missfire

[mrtjet]

My 08 Silverado 4.3 auto has a misfire on acceleration more so if I push it above 2500 rpm or so. Seems to idle fine and lite and accelerate it seems fine. The harder I push it the crappier it runs When I scan it I get the 0449 code as I mentioned in an earlier post. I am getting the parts for that. Could that code be related to the misfire? Also scanned says number three cylinder misfire.I installed a New plug wire with no change. I took a shot and replaced the gas cap as I read that could set the 0449 code. I realize that this is rather vague info but perhaps someone could help. Personally I'm leaning towards a coil pack for the miss. Back in the day we would spray silicone spray on the cap and wires to test for bad caps and wires. Could that help diagnose this miss? Thank you.