I'm 99% sure my engine is misfiring on a cylinder or two. I doubt it's the plugs or the wires. I took all 8 plug wires 1 by one and took them off, held the end of the boot about a cm away from the spark plug, and there was a nice blue spark arcing from the boot to the plug. I think I may have a rounded cam lobe or two. The motor does have a rowdy cam @ .469/.469 lift , 268 duration on intake and exhaust, but you can see it shaking left to right when it misses. My engine's doing the shimmy and I don't really like it. I wouldn't be surprised if it was a rounded lobe or a few, I forgot the oil galley plugs when I first built the motor and broke the cam in with barely any oil getting to the top end. I replaced them almost immediately, but the damage was probably already done. It seemed to run as well as it ever has a few days ago, but recently it's become more noticeable especially at idle and part throttle cruising. I don't have a video to describe it, but imagine buh-buh-buh-bbuh-buh-buh-bbuh-bbuh, and that's what it sounds like. I've never had any shiny bits or shavings in the oil that I've seen or in the filters I've cut open. But I rev this thing past 5500 more often than Buick ever intended so it's not a shot in the dark. The RPMS also fluctuate 100rpm or so up and down and it never used to do that. What say you guys?