ignition problems!!! HELP!!

that sounds like a blown head gasket. If you have a V6 mustang that was a VERY common problem. Open your radiator cap and see if it bubbles while it's running. Also check the oil and see if you can see any coolant/fluid other than oil in there...if it's a chocolate milk color, that's very bad. you can also try a compression test/leakdown test to verify which cylinders the gasket has blown. A blown head gasket will cause poor running/pinging under acceleration and as the gasket gets worse, it runs really bad and white smoke will come out of the exhaust. And as you could tell the fuel is alot harder to ignite with water in the combustion chamber. 1 main thing is to stop driving your car until you get this replaced. Driving it like that can warp the heads, score cylinder walls, etc. Good luck and i'm sorry to hear your misfortune.