Hyundai Repair: oil leak and pressure leak, pcv system, pressure leak

Question
hello, i have a hyundai 1.6 DOHC engine (16v), i have tremendous engine leak(approx 1 litre engine oil loss every 350 to 400 kms),the engine oil reaches the air filter compartment, the car gives jerks while accelerating. i checked the compression through a gauge which showed 15 pounds pressure in 1 valve, 13 on another, 11 on the other and 12 on the last. pls advise why this is taking place and what should be done.is it the piston rings, the piston, the boring or just a gasket leak, ....  

Answer
First, check for external leaks.  You'll need to try to determine how much oil you're losing externally and how much is coming out the intake into the air filter.

Second, check your PCV system.  Make sure the PCV valve allows suction to the crankcase.  Make sure the PCV chamber in the engine isn't clogged with sludge.  And make sure the PCV breather hose isn't clogged.

Getting oil all the way back to the air filter area is a troubling amount of oil in the intake area.  If your PCV system is working properly, it's pretty safe to say that you have a problem either with the piston rings or cylinder walls.