Re power loss - I had a similar thing after filling up the tank from very low level.
It was debris in petrol.
Symptom was - revving ok to about 2000rpm but then above that engine seemd to be starved of fuel and "hunted" - revs varying up and down. A tank flush cured the problem.During the flushing some debris was found when filtering the petrol. I think this was causing partial blockage and fuel starvation when high demand was made.
