Just did head gasket in 1993 4 runner with 94 22re in it. the engine has 220000 km. It is strugling in power between 3rd and 5th. ( 5 speed manual trans) could the vacum be hooked up wrong? there is no knocking at idle and it running smooth at 750 rpm. timing is set to 5 BTDC. the truck has 35" tires and 5" lift with 4:10 gears. Is the weight of the tires giving me the bog between gears or is it the timing?