CITROEN C2 PROBLEMS AGAIN........HELP?

My citroen is back firing and some water or petrol dripping from exhaust when I rev it. The steering then goes heavy when trying to move off one minute and then when i turn ignition off and back on again it eventually is ok, but now it is losing power on accelaration so i cant drive it. Help, ive checked oil, water and run engine diagnostics as engine fault light coming on but no detection of problems could it be spark plugs