sometimes smokes, sometime doesn't

avgtiger

i have a 2000 sonoma with a 2.2. it suddenly started blowing smoke and oil out the oil filler neck, even with the dipstick in. also, as i am driving, it will suddenly start burning oil leaving a trail of smoke. the smoke goes away, then comes back

avgtiger

also, i changed the pcv vale, which was no easy task. it is between the intake and the head. this did not help.