I’m bumfuzzled. Finishing my 84k service, after fluid changes, new plugs, fuel filter, ig timing, adj valves. Took an initial 10 mi. ride, topped up with a gallon of 93, all was great. Then finished by checked throttle cable slack (no change other than 1mm choke slack) throttle bodies opening in sync. But now it has a bad idle with misses & backfires at tailpipe and snorkel. Adjusted valves again, still bad idle, but runs clean once warm and past +-2,000 rpm. Still cuts out at idle. Any thoughts?