[JBO]

OK, I've read all the archives, and have been adjusting my mixture for a few seasons after having it professionally set - richen a little in fall and lean a little in spring. My question - this past weekend when it was particularly cold - 20 in the morning - car was hesitating and backfiring slightly until warm (which to me indicates lean). Once when I started it warm it backfired a little, I "think" in the intake. It also has become harder to start - have to hold the key in start position longer, when previously it would always start immediately. However, once warm I had some slight popping from the exhaust on decel, and can't find any leaks, which indicates rich. When I went to Souks "field test" and lifted the sensor plate, the engine RPM's increased and the engine raced a little, which indicates lean. So, I think I need to richen it up a bit, despite the exhaust popping. FYI I have a cat by-pass and GHL muffler.