Misfire P0304

[ZO6_Vette]

Hi,
Looking for some opinions on where to go from here.
2006 Explorer 4.0 43,000 miles throwing P0304 code.
It seems that that the fault only happens a very short time after start up.
If I clear the code it will not happen again until the car sits for a while and restarted.

Did a compression test on cylinders 4 and 5 and they were identical at 155.

I have replaced the coil, wires and plugs, sprayed around the intake manifold and found no leaks.

I did a power balance test using my Autoenginuity scanner and it showed all cylinders were fine.

Below is the freeze frame data for 3 instances of the fault notice the run time.



Vehicle Manufacturer: Ford
Vehicle Calibration ID: PWFG0AB.HEX

1)..................................
Freeze frame information:
------------------
Fuel Status = 0 byte
Engine Load = 87.843 %
Engine Coolant Temperature = 172.4 °F
Fuel Trim Bank 1 Short Term = 0.781 %
Fuel Trim Bank 1 Long Term = 2.344 %
Fuel Trim Bank 2 Short Term = -2.344 %
Fuel Trim Bank 2 Long Term = 1.562 %
Intake Manifold Pressure = 12.473 psi
Engine RPM = 2,324 rpm
Speed (OBD) = 27.34 mph
Timing Advance = 18.5 °
Intake Air Temperature = 86 °F
Mass Air Flow Rate = 483.85 cfm
Throttle Position(Manifold) = 30.98 %
Fuel trim bank 1 sensor 1 = 0 %
Fuel trim bank 2 sensor 1 = 0.781 %
Run time since engine start = 64 s
Fuel Rail Pressure (relative to manifold vacuum) = 54.344 psi
EGR Commanded = 0 %
EGR Error = 0 %
Fuel Level (From Engine ECU) = 28.627 %
Distance travelled since codes cleared = 3,063.981 miles
Evap System Vapour Pressure = -51.5 Pa
Barometric pressure (from vehicle) = 14.939 psi
Catalyst Temperature (Bank 1,Sensor 1) = 1,061.24 °F
Catalyst Temperature (Bank 2,Sensor 1) = 1,061.24 °F
PID: 41 = 0
Voltage (Control Module) = 13.864 V
Engine Load(Absolute) = 62.745 %
Commanded Equivalence Ratio = 1
Relative Throttle Position = 18.431 %
Ambient air temp = 66.2 °F
Absolute Throttle Position B = 50.196 %
Accelerator PedalPosition D = 33.725 %
Accelerator PedalPosition E = 40.392 %
Accelerator PedalPosition F = 29.804 %

2)..................................
Vehicle Manufacturer: Ford
Vehicle Calibration ID: PWFG0AB.HEX

Freeze frame information:
------------------
Fuel Status = 0 byte
Engine Load = 63.137 %
Engine Coolant Temperature = 181.4 °F
Fuel Trim Bank 1 Short Term = 1.562 %
Fuel Trim Bank 1 Long Term = 3.125 %
Fuel Trim Bank 2 Short Term = 0 %
Fuel Trim Bank 2 Long Term = 2.344 %
Intake Manifold Pressure = 10.008 psi
Engine RPM = 2,074.5 rpm
Speed (OBD) = 11.185 mph
Timing Advance = 29 °
Intake Air Temperature = 80.6 °F
Mass Air Flow Rate = 287.727 cfm
Throttle Position(Manifold) = 23.922 %
Fuel trim bank 1 sensor 1 = 3.125 %
Fuel trim bank 2 sensor 1 = 0.781 %
Run time since engine start = 62 s
Fuel Rail Pressure (relative to manifold vacuum) = 54.423 psi
EGR Commanded = 51.765 %
EGR Error = -3.906 %
Fuel Level (From Engine ECU) = 98.039 %
Distance travelled since codes cleared = 35.418 miles
Evap System Vapour Pressure = 17 Pa
Barometric pressure (from vehicle) = 14.794 psi
Catalyst Temperature (Bank 1,Sensor 1) = 1,006.34 °F
Catalyst Temperature (Bank 2,Sensor 1) = 1,006.34 °F
PID: 41 = 0
Voltage (Control Module) = 13.966 V
Engine Load(Absolute) = 43.529 %
Commanded Equivalence Ratio = 1
Relative Throttle Position = 10.98 %
Ambient air temp = 60.8 °F
Absolute Throttle Position B = 35.294 %
Accelerator PedalPosition D = 28.627 %
Accelerator PedalPosition E = 36.471 %
Accelerator PedalPosition F = 25.49 %

3)................................................
Vehicle Manufacturer: Ford
Vehicle Calibration ID: PWFG0AB.HEX

Freeze frame information:
------------------
Fuel Status = 0 byte
Engine Load = 21.961 %
Engine Coolant Temperature = 170.6 °F
Fuel Trim Bank 1 Short Term = 3.125 %
Fuel Trim Bank 1 Long Term = 7.031 %
Fuel Trim Bank 2 Short Term = -0.781 %
Fuel Trim Bank 2 Long Term = 3.125 %
Intake Manifold Pressure = 4.496 psi
Engine RPM = 704.25 rpm
Speed (OBD) = 0 mph
Timing Advance = 27.5 °
Intake Air Temperature = 100.4 °F
Mass Air Flow Rate = 32.406 cfm
Throttle Position(Manifold) = 14.51 %
Fuel trim bank 1 sensor 1 = 3.125 %
Fuel trim bank 2 sensor 1 = -0.781 %
Run time since engine start = 84 s
Fuel Rail Pressure (relative to manifold vacuum) = 56.202 psi
EGR Commanded = 0 %
EGR Error = 0 %
Fuel Level (From Engine ECU) = 83.137 %
Distance travelled since codes cleared = 19.263 miles
Evap System Vapour Pressure = -86 Pa
Barometric pressure (from vehicle) = 14.794 psi
Catalyst Temperature (Bank 1,Sensor 1) = 629.42 °F
Catalyst Temperature (Bank 2,Sensor 1) = 629.42 °F
PID: 41 = 0
Voltage (Control Module) = 13.889 V
Engine Load(Absolute) = 15.294 %
Commanded Equivalence Ratio = 1
Relative Throttle Position = 1.961 %
Ambient air temp = 59 °F
Absolute Throttle Position B = 16.863 %
Accelerator PedalPosition D = 18.824 %
Accelerator PedalPosition E = 29.02 %
Accelerator PedalPosition F = 18.431 %

 

[Chikar]

DTC Code P0304

--------------------------------------------------------------------------------
DTC Code:

P0304

Description: Cylinder 4 Misfire Detected

Probable Causes:

1.Update control unit software - Check for the latest control unit update
2.Powertrain or Engine Control Module faulty
3.Fuel injector(s) faulty
4.Ignition system - Ignition module, coil, spark plugs and wires
5.Fuel system

Since you've taken care of number 4 I'm leaning towards number 3, a bad fuel injector or it's wiring.

It can't hurt to check number 1, control unit software update either but I'd be more inclined to think it's a mechanical problem than electronic i.e. the injector.