Very wierd issue...1997 chevy blazer ls. Recently put new motor into it...fixed a **** load of problems. Its been running perfect...except the maf sensor has been getting oil on it from the crank case vent. Its quite a distance from the passenger side valve cover(crank case vent goes into it) to my maf sensor. Normally an engine with back pressure like that has worn oil rings...my motor has 10,000 miles on it...ANy idea what would cause oil to travel from crank case vent...down the air flow duct into the maf sensor...? With too much oil on the MAF it runs rough and sometimes wont start! Also with oil on the MAF check engine light comes on and reads trouble codes for EGR MAF AND TPS. clean the oil off the MAP check engine light goes off and it purrrs.