I have a 1997 S10 with swapped to an LQ4, 243 P&P heads, shorty headers, 2.5" true dual exhaust, elgin E-1838-P (.560" lifts, 216/220 114 LSA), cold air intake. I feel a constant misfire at idle and through the lower RPM ranges, but no codes, no misfires show in the counters in the VCM scanner or my Snap-on scanner. And not a "hard" misfire, either. Just a constant vibration like maybe one cylinder just isn't keeping up with the others. A little background: This truck had a L59 with a cam and 706 heads before. The truck worked beautifully. I built this 6.0L and basically swapped the long block. At first I didn't pay much attention to the little roughness because the L59 kind of behaved like this until I got the tune right. I have the engine broken in and actually tuned with a wideband today. I used the high and low octane spark tables from a Z06 (since it's sort of a similar setup and my other timing table was kind of radical) I got my MAF and VE errors to where they are close, but noticed that the misfire feel didn't get any better. so I stopped tuning and started checking things. I found two coils were acting a little weird, so I changed them... no change. Checked all the wires, connectors, ect. Nothing out of place of making poor connections. I do notice a little lifter noise right around the 2000 RPM area, but my old engine literally sounded the same and these are new lifters, the preload is just past 1 1/4 turns on the rocker bolts. I attached the last adjustments I made to the tune, and the log file from right before. Any help or places to check would be greatly appreciated.