Lost most engine power ,need advise
 

Hello this is what happen just a few hours ago ,I was driving on the highway and just out the blue the engine just went sluggish ,still going but no reaction ,I stop at a gas station check the vacumm hoses ,(just finish replacing a few) see in one came loose but no is all good ,but sounds like **** ,noise from the top where the spark plugs are ,got back on the highway a drove another 20 miles home ,it gets up to 65mph but slowly ,once home plug my OBD2 but no code , it sounds like valves tapping hard right on top ,even when you press the gas pedal it doesn't go up on the rpms like it should sluggish even in neutral ...any ideas?? Im about to junk this thing ...is a 98 V70 XC ..thanks