my volvo s80 petrol 2.4 petrol . just developed a fault, no power , revs up on its own to 2500rmp then goes back to idle. had to more or less roll home. engine managemnet lights on and says emission system or something like that, sounds like its not running on all the cylinders, friend suggested split air pipe possibly., could anyone help me with some guidance here. im no mechanic but i can follow some guidance . me number is 07706577227