I don't know anything about the filters causing a problem but I had trouble
with oil in the intake. The PCV gasket in the valve cover leaked and caused
oil to enter the intake manifold resulting in carboning the AAC valve and
created a bad idle for me. The intake manifold had oil in the bottom and I
am sure has created carbon on the piston tops. It also dirtys the oil
quicker and introduces contaminates onto the cylinder walls and wears the
rings out quicker creating oil blow-by. I have an extra motor that I pulled
apart and found 2 mm of carbon on the pistons. I looked at the plugs
condition and they were clean, so I looked at the PCV gasket and it was
damaged and lots of oil was in the intake manifold at the bottom. The
runners were also oiled up.
Check the condition of the gasket for anyone. The gasket is
cheap and could solve many problems with emissions. The gasket is a small
retangular item near the front of the cover in the center front edge.
Chris 92 classic
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