Engine stalls and tmp guage goes nuts
have a 97 f150 that will run (idle) ok but sometimes (usually after it warms up) the temp gauge will start bouncing all over and engine either stalls or runs really rough. I can happen even hen driving. Then a relay starts to chatter and it sounds like the injectors are firing. Have changed plugs, plug wires, and fuel filter, ad drained gas and put new in.