ORIGINAL: Hershey

Check the crankcase breather hose to see if it is plugged, it should be connected to the airbox on the right side.

If that's not the case, you've probably got excessive blow-by and/or badly worn valve guides... it can also rarely be caused by a totally plugged oil filter.

Do a compression check on all cylinders and get back to me... if your numbers are low put a few drops of oil into each cylinder and test again.