ok, I tuned my '02 t/a with free m air mod, lid, full td exhaust, and ported maf w/screen last year and everything was about perfect. Recently though, as the weather has warmed up, i have started seeing a LOT of knock in the lower rpm range. Tuned last year in much warmer weather than what it's been so far this year. Checked plugs and wires and there are all good. Using tr55's gapped at .045. I am just at a loss on what to look for. WOT is clear of any knock as well.