i have a 03 150 v max efi my motor sometimes losses power at top end have only had boat for 4 weeks have 25 tempest only showing 5200 to 5400 rpm but when motor cuts out 5000rpm most it will do from read post i hear about rev limiter mabe o2 sensor not sure what to do first also wondering if i need special tools to take off o2 sensor and do i need a new gasket or can you just put back on with old gasket. want it to be known to original owner of boat never ran boat over 5000 rpm was afraid of hurting motor any feed back would be appreciated