2008 Sport Trac Misfire & Bank System Too Lean

[Pharbach]

Had a #2 cylinder misfire (P0302) history. Recently got the truck, so replaced plugs & wires. Problem still existed, so I threw a coil pack at it. Same problem, but now I get a "Bank 1 System Too Lean" (P0171). Cleaned MAF sensor, no help. Searching for PCV. I know it's near the firewall on drivers side, but where? OBD Live Data shows REL FRP (Fuel Rail Pressure running between 36PSI @ 41PSI. Is this in norms, and is the fuel pressure variation normal?
I'm actually suspect #2 fuel injector is causing the misfire and Bank too Lean codes.
Truck runs okay I guess, but I can sense a shuddering and loss of power due to the engine missing on and off.
Any help would be great!
=Paul

 

[DILLARD000]

Need to spec your Engine+Tranny+TCase+Diffs+... in your profile & in these threads;
folks much more likely to answer your questions if not having to ask\dig for that info.
Assuming you've the V6~4.0L~SOHC ?
How old are OxSensors? They last ~100kMiles\10years then start generating TroubleCodes.
PCVValve is on the rear end of the left ValveCover in a tight space next to the FireWall,
need a new one or at least clean it every 33kMiles\5years.
PCVHose elbows are also known to crack+leak generating p0171+p0174 codes.
IntakeManifold gaskets can also leak & generate these codes.

 

[Pharbach]

Dillard,
Yes, it's a V6 SOHC.
Thanks for the PCV valve location. Saw it, but yes, it's a tight squeeze back there against the firewall to remove it. Will check the other elbows for leaks.
What are your thoughts about a #2 fuel injector problem. Thats the only cylinder misfiring on the left bank of fuel injectors that shows lean.
Have no O2 sensor faults. Why would that cause a misfire or bank lean. If there was O2 problem it would have coded.

 

[DILLARD000]

...thoughts about a #2 fuel injector problem. Thats the only cylinder misfiring on the left bank of fuel injectors that shows lean.
...no O2 sensor faults. Why would that cause a misfire or bank lean. If there was O2 problem it would have coded.

Injector2 could be it; inspect for bad wiring, then try a bottle of InjectorCleaner & PremiumGas fillup (money!). If that doesn't work, renew it.
As OxSensors age, they loose ChemicalCoating, tend to bias lean & drive Air~Fuel mix rich, MPGs decrease, CatCons run too hot, eventually code gets generated. If OxSensors are >100kMiles\10years, renew them.

 

[Pharbach]

Dillard,
I've been overdosing the gas with LUCAS Injector cleaner and fuel conditioner for the past several weeks for the initial misfire issue (without the bank lean issue), as a clogged/dirty injector or rail could have been the culprit. The misfire seems to be intermittent now, so an audible test of injector may prove to be a false positive.
Someone else suggested replacing the PCV valve and the fuel filter. He said the full rail pressure I had stated (38-42) was a little low and suggested replacing fuel filter. He also suspected a manifold leak near the EGR valve on the rear of the manifold and suggested a smoke test.
My first order of business is to replace the PCV valve and check its lines for cracks, then replace fuel filter, then the #2 injector.
Learned to go from easiest to hardest...
What do you think?

 

[Pharbach]

Injector2 could be it; inspect for bad wiring, then try a bottle of InjectorCleaner & PremiumGas fillup (money!). If that doesn't work, renew it.
As OxSensors age, they loose ChemicalCoating, tend to bias lean & drive Air~Fuel mix rich, MPGs decrease, CatCons run too hot, eventually code gets generated. If OxSensors are >100kMiles\10years, renew them.

Dillard,
Just to nail down PCV valve location.
Photo #1 shows drivers side manifold location. Is the PCV valve directly on the manifold (where the green release is?), or is it BEHIND the manifold (photo #2). Can't get a picture of it due to inaccessibility. Is the PCV valve a heated unit? If so, it's a $50 part. Does the manifold have to come off to replace the PCV valve?

 

[DILLARD000]

Your 2008 likely has the ElectricHeated PCVValve.
Unsure about access, as the IntakeManifold is different on your later year model.
Crazy stupid location for that PCVValve.

 

[Pharbach]

Dillard,
I think I'm gonna have to eff around and find out.
Taking of the plastic manifold will expose all that mess so I cam really be sure.
Why they chose to put the PCV valve back there is the engineers fault for not thinking about routine maintenance.
It's sure not maintenance friendly at all....

 

[blert]

The PCV valve should be on the driver's side valve cover, in the back between it and the firewall. Pop off the hose and give it a twist. It's a bit of a pain but doable.
If you have the time and gumption you could swap #2 injector with another cylinder and see if the issue follows the injector. If not then you know it's not the injector and you don't need to spend the money on a new injector.

 

[Pharbach]

Dillard,
Haven't gotten to the fuel injector swap or PCV valve (yes, VERY difficult to remove all of the way. Firewall blocks complete removal), but replace fuel filter. Old filter has very dark fuel cone out of the IN side. No help, but now it's done. Dide Live Data scan on O2 Sensors. All were normal volts, except O2 sensor 12. At idle the voltage read 0.050 volts, and 3400 RPM (max RPM in park), it still read 0.050 volts, while other sensors increased in voltage. Trying to go from easiest to hardest. If this doesn't fix, I'll move onto the fuel injector #2....

 

[DILLARD000]

Likely need to pull hose off PCVValve first, then quarterturn CCW, to remove.

 

[Pharbach]

Well, I'll try again.
The foam insulation around the elbow tube makes it difficult when it his up against the firewall.
I'll eff around and find out!

 

[Pharbach]

Dillard,
I guess I'm lost!
Please view the first photo with the vacuum hose disconnected from the manifold. Where is the PCV valve located in reference to this location?
Amazon sez I need this heated PCV valve.
It's very difficult to see anything back behind between the cast edge of the manifold and firewall.
Will I have to remove the manifold to gain access to the PCV valve? If so, its pretty piss poor engineering!

 

[DILLARD000]

Below are vids on changing Electric PCVValve on later model year 4.0L Engines.
Access is limited, but seems do-able without removing the IntakeManifold,
just do it more by feel than by sight, on the back side of the Manifold & ValveCover.
I'd also renew that short elbow hose when replacing the PCVValve.