also check the 3 pipes from the amal valve as the one that routes into the a/f meter pops out time to time
check the vacum pipe that leads to the ecu as this catchs the heater box and creates a small hole init
also my throttle body had a small air leak to by the switch
are you still running the standard breather as these tend to leak around the breather itself and by the gearbox
is the dipstick pushed in nice and tight