When you took the oil cap off of a car you felt a lot of air being pushed on your hand Is that a bad sign If so what does that mean is wrong?

Answer

No, this is very normal. I had a BMW that would stall if I removed the oil cap while running. The mechanic told me that that car was so finely tuned that the loss of pressure escaping out the cap throws off the whole balance of the system.

This would signify a plugged PCV system, there should never be pressure in the valve cover, this could cause seals or gaskets to leak.