Anyone have any thoughts on this: The engine starts fine and runs smooth for about one minute then it develops a miss and runs rough from idle until about 3000 rpm. Above 3000 it smooths out and developes good power . Runs fine in cruise until you pull it back for landing when it starts running rough again. I've had the carbs rebuilt, the gearbox rebuilt and have syn'ed them to death but I still can't get it to run smooth below 3000rpm. I've changed the carb boots and checked for induction leaks. I'm running out of ideas
Thanks
EG