Most of the time it runs fine. Intermittent hard to start; rough running, tach at idle 1K. As soon as I press gas, tach jumps to 4K. Engine dies at highway speeds. 2 dealers can’t find the problem. Changed fuel filter, used “Heat” to remove water, substituted MAS, dist. cap and rotor, coil, resistor. Code reads 55. Dealer in Lubbock said the EGR was working fine.
Tried to start while the vehicle was malfunctioning. With the key in the run position and the motor not running, tach read 1K. Also fuel pump continued to run and you could hear a soft clicking from one of the injectors. When it wasn’t malfunctioning and the key in the run position, the fuel pump would stop when it pressurized and you couldn’t hear the injector clicking and the tach reads 0K. Could it be the ECCS? Checked code again. Still getting code 55.
Vehicle has 169,000 miles.