Are you using 10%ethenal gas in your car? If so you need to drop your a/f ratio down to 13 to 13.5. When driving at 2000 rpm and drop 12 to 12.5 is fine. When I open up my six pack I drop to 10.5. When hot at idle 1000 rpms I'm at 13 to 13.5. I use two gauges one in each header down at the collector. I run a 340 six pack 3500 stall in the tranny.