I have 92 22re that I have just noticed air coming out oil hole on valve cover but not the dipstick hole when I was checking the pvc valve or no oil leaks seems like pressure just in valve cover I've had a random miss and engine runs great but can' find source of random miss now I'm wondering if have serious internal issues or is it something stupid I'm missing cause honestly it runs fine other than that random miss when it warms up anyone have similar problem or advice before I tear this motor apart!!

 

I had a 1973 Datsun that air or compression came out the oil fill cap but I was told this was normal since it had the overhead cam. I don't know if they were right or not but it sounds reasonable and I drove the truck for many,many years with no problem. The engine was still going strong when I sold the truck but the body was shot.