2004 GT 4.6L,stock except for a 3.73 axle. The large "Nipple" on the right side of the intake at the firewall broke and was spewing coolant.I replaced the "underneath" heater tube and its O-ring part behind the water pump, the water pump itself, 8 spark plugs,both heater hoses,and the manifold from Ford Racing. I just cleaned the fuel injectors externally. All anti-seize,sleeve retainer,Silicone dielectric,etc.,were utilized correctly,& everything gapped,cleaned,and adjusted appropriately. So now I've gone from 19.5 mpg to 8.5mpg in 95 miles.No fuel odor. The engine runs somewhat erratically,with a "pop pop pop" idle. I have to either get an OBD-II device or pay the man to check codes,or get a new set of injectors--or who knows what. Any thoughts on this?