prheath

2005 F-150 5.4L
Lariat

I've been chasing the following issues for like a year now:
1) Almost always has a open loop misfire (always 4 and or 8) that clears on its own once engine warm up.
2) Always hesitates on moderate to heavy acceleration
3) Often backfire through intake on moderate to heave acceleration
4) General lack of power - can barely power brake even in dirt/grass (I know, why would I want to - was just trying to see if I had enough power to)

I did each of the following individually with slight improvement in power and millage.
Replaced Plugs and coils
Ran injector cleaner
Replaced Injectors
Replaced fuel filter
Ran Top Engine cleaner (Sea Foam)

I began trying to really pay attention to freeze frame data and realized that it appears my catalytic converters are not really doing anything. The downstream wave forms don't look as different from the upstream as I think they should. I am going to try to attach pic. I think 1 and 2 are upstream with 5 and six being downstream.

Can someone please tell me if look like I am on to something?

Ludo

Hello
I have the same problem as you.
On my 5.4 from 2007.
I found that my o2 Aval sensor reproduces virtually the same data as the upstream sensor.
It launches me the code P0420 and P0430
I note by looking at the flow of data that fuel loop No. 2 indicates N / A
I can not understand why loop 2 does not indicate (closed)
Data frozen at the time of P0420
Fuel sys 1----------------------------> closed
Fuel sys 2----------------------------> N/A
Calc Load%------------------------->51.8
Coolant (°C)-------------------------->90
ST FTRM1%------------------------->0.8
LT FTRM1%------------------------->0.8
ST FTRM2%------------------------>4.7
LT FTRM2%------------------------>-2.3
Engine speed---------------------->1252RPM
Vehicule speed-------------------->58KM/H
Ign ADV(°)-------------------------->36.5
IAT (°C)------------------------------>19
MAF (GR/S)------------------------>15.99
ABSLT TPS (%)------------------->17.6
O2S11 (V)--------------------------->0.670
ST FTRM11 (%)------------------->1.6
O2S12 (V)--------------------------->0.595
O2S21 (V)--------------------------->0.090
ST FTRM21 (%)------------------->3.9
O2S22 (V)--------------------------->0.645
Engine run (M:S)------------------>04:26
Rel FRP (KPA)--------------------->264.57
EVAP PURGE (%)---------------->57.7
Fuel level (%)----------------------->78.8
Clr TRPS---------------------------->2
Clr Dist (KM)------------------------>68
EVAP VP (Pa)---------------------->-334.750
Baro PRS (KPA)------------------->100.0
Cat temp11 (°C)-------------------->577
Cat temp21 (°C)-------------------->577
VPWR (V)---------------------------->14.195
Absolue load value (%)----------->23.9
CMD EQ RAT------------------------>0.999
REL TPS (%)------------------------->4.3
Out temp (°C)------------------------>8

prheath

The only codes I ever get are P0304, P0308 (and rarely P0300).
Here is recent freeze frame data:

Long term fuel trim—Bank 2: 7.03 %
Engine RPM: 2112.0 rpm
Vehicle speed: 41.61 mph
Timing advance: 26.0 degrees
Intake air temperature: 95.0 F
MAF air flow rate: 63.85 g/s
Throttle position: 27.1 %
Oxygen Sensor 1 Voltage: 0.78 V
Oxygen Sensor 1 Short term fuel trim: 2.34 %
Oxygen Sensor 2 Voltage: 0.73 V
Oxygen Sensor 5 Voltage: 0.08 V
Oxygen Sensor 5 Short term fuel trim: 9.38 %
Oxygen Sensor 6 Voltage: 0.07 V
Accelerator pedal position D: 38.82 %
Accelerator pedal position E: 44.71 %
Accelerator pedal position F: 34.51 %
Commanded throttle actuator: 23.14 %

My LTFT usually sits around 20% or more on bank 2

Ludo

Have you ever tried to do a driving cycle?
When I bought my truck, I launched several codes. I solved them by doing a driving cycle. Since that day he has just launched me the cat codes
I guess you know the exact procedure. But I allow myself to give you the link of the procedure.
http://www.obdii.com/drivecycleford.html

Ludo

When you changed your plugs did you clean the nuts?

prheath

I will see if I can run the drive cycle.... sounds like it takes some coordination.

What do you mean by "...clean the nuts"? Do you mean the contacts for the COPs?

Ludo

the driving cycle worked well for mine.
I wanted to talk about the holes in the head. the one where the plug is aimed.
if the hole of the head is not perfectly clean the plug does not have a sufficient ground to work well. with your scanner can you control the percentage of misfire?

prheath

I didn't do anything to the threads for the plugs. Once I "broke" them ,they easilly came out with fingers as well as threading new ones in - was able to do by hand until they were flush. Didn't feel any binding or any indication of dirt/grime.
For what its worth, the misfire also happened prior to replacing plugs.

Ludo

[QUOTE = prheath; 5905682] Je n'ai rien fait pour les threads des plugs. Une fois que je les ai "cassés", ils sont tout simplement sortis avec les doigts et en ont enfilé de nouveaux. Je n'ai ressenti aucune contrainte ou indication de saleté / saleté.
Pour ce que cela vaut, le raté a également eu lieu avant de remplacer les bouchons. [/ QUOTE]
have you ever tried to reverse the cops?

prheath

Had same misfire pattern prior to replacing all COPS. Symptoms have always been the same before, during, and after attempts to repair. Iv'e only ever managed to increase power and fuel economy slightly. Iv'e just never been able to affect the misfire.

During all of this, I did have a VTC fail, I replaced it and still had same misfire. If only misfire was on same side of block, but always both sides.