I have a Volvo 850, believe it’s a 1996, car usually ran rough, but recently i went to start it and it will run for about 4-6 seconds and die out, and the dip stick and oil cap have some considerable suction after every time the car dies out. Could this be the PCV needing cleaning? Or does the Idle Control Valve need replacing? I have already put fuel stabilizer in the car and it will run longer when starting fluid is added…