Ok so I took out the 6.2 out of my 07 Sierra 2wd Auto and installed a stock 5.3 with DOD... I put a completely stock tune except for raise the shift points a bit and of course moving the TQ Managment. But now what I have noticed is that now at idle sometime you can hear a little miss, and on WOT starting around 5000rpm is starts bog/stutter/misfire. While scanning no DTC's come out but the CEL blinks then goes away by itself then drives normal after 30 seconds or so. PE, Timing, AFR are all at stock parameters. Anyone ever run into this problem?

*My guess is the spark plugs since I reused the ones off the old 6.2 but then again I'm not sure. I'm going to replace them tomorrow.