While car is running grey smoke comes out of the exhaust. I just did a tune-up to it and now it. when I take it for a drive the smoke pours out more and the car seems like it is choking itself out. I doubled checked all the plugs and wires and they are fine. I checked for a blown head gasket and the coolant and oil look fine. When I put my hand next to the exhaust it looks like oil is spitting out. Please help I just bought this car. Thank you