When my '92 EB with the 4.0 V6 has been sitting for a while it will run rough when I first start it up and white smoke comes out of the tailpipe. There is oil in the intake (the plastic tube that goes from the air cleaner to the intake manifold) where the crankcase breather is connected to it. After it runs for a while the white smoke goes away and it runs smoothly (well, smooth for 280K miles on the engine).
I replaced the PCV valve but it didn't seem to make a difference. What can cause oil to get in there? The oil level in the crankcase is normal.
Thanks.