Ford Code P0304 2004 Ford F 150 5.4L Triton, 2wd

Ford F-150I have 2004 Ford F-150, 5.4 Triton V8. When I run it from cold start it runs fine for a bout 20-30 minutes. Once it warms up, it starts to sputter and stall out. Also, while driving when come to a stop, it stalls. We took the electronic throttle body apart, replaced the throttle position sensor, cleaned the body, and replaced the motor, all but buy a whole new throttle body. Cleaned the MAF as well. Had a cylinder 4 missfire and a camshaft sensor code come up so replaced both. I am at my witts end here and am about to pull out my hair because of this. Also replaced all of my spark plugs. Can someone please help.


I might lean toward the ECT – Engine Coolant Temperature Sensor since it runs fine until it warms up. This can be caused by a stuck sensor reading. If the PCM continues to be told the engine is still cold once it has warmed the PCM doesn’t know and continues to flood the engine with incorrect amounts of fuel.

Engine Coolant Temperature (ECT) Sensor

An Engine Coolant Temperature (ECT) Sensor is a thermistor device in which resistance changes with temperature. The electrical resistance of a thermistor decreases as the temperature increases, and the resistance increases as the temperature decreases. The varying resistance changes the voltage drop across the sensor terminals and provides electrical signals to the Powertrain Control Module (PCM) corresponding to temperature.
Thermistor-type sensors are considered passive sensors. A passive sensor is connected to a voltage divider network so varying the resistance of the passive sensor causes a variation in total current flow. Voltage that is dropped across a fixed resistor (pull-up resister) in series with the sensor resistor determines the voltage signal at the PCM. This voltage signal is equal to the reference voltage minus the voltage drop across the fixed resistor.

The ECT measures the temperature of the engine coolant. The PCM uses the ECT input for fuel control and for cooling fan control. There are 3 types of ECT sensors; threaded, push-in, and twist-lock. The ECT sensor is located in an engine coolant passage.

Ford Code P0304 – Cylinder 4 Misfire Detected

Ford Code P0304 Possible causes

•Faulty spark plug 4
•Clogged or faulty fuel injector 4
•Faulty ignition coil 4
•Fuel injector 4 harness is open or shorted
•Fuel injector 4 circuit poor electrical connection
•Ignition coil 4 harness is open or shorted
•Ignition coil 4 circuit poor electrical connection
•Insufficient cylinder 4 compression
•Incorrect fuel pressure
•Intake air leak

The Ford Code P0304 means that the cylinder 4 is misfiring or is randomly misfiring. Start by checking for intake leaks an if no leaks are found the next step is to replace the spark plugs on cylinder 4.

1 thought on “Ford Code P0304 2004 Ford F 150 5.4L Triton, 2wd”

  1. Check your oil for water residue or white froth on the cap. I had the excact same issue with my Ford and it ended up being a blown gasket.

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