Why dose my oil cap smell like gas

Smell of your crankcase oil dipstick. If it smells like gas, I wouldnt drive it till you fix the problem. Do you change the oil and filter regularly? Where applicable, check the vacuum line for the fuel pressure regulator, if gas in the vacuum line, replace the regulator. Use a gage and check for correct fuel pressure. Also, check that the pressure will hold for a bit, with everything off.

After you fix the problem, change the oil and filter as many times as necessary to remove the gas smell.