does it start up okay without any issues? if your getting very weak acceleration and starting with a bit of a stumble every now and then on idle I’d check the plugs, fuel system and filter which you’ve already done and air intake first of all. could check for any clogged oil lines, I know you’ve ran sea foam but if there was already a pretty bad blockage then using it to loosen up other deposits may have collected in the same place. compression could also be a tad low, is your oil consumption normal?