I cannot locate a thread addressing these issues. My 99 F250, 5.4L runs fine at start up but, severely misfires after warm up (2 or 3 miles). It is showing codes P0174, P1151, P1150 and P0308, P0305 and P0307. Issue is with one bank only. I'm looking for opinions before I dive in and start blindly replacing parts. A visual inspection shows nothing obvious. The problem is recent with no issues prior to this. My next step is to pay for an OBD diagnosis.

 

Something is definitely going on with bank 2.
Cylinder #7 is on bank 2, but is not connected to the #5 & #8 thru the intake.
Cylinders 3,2,5,& 8 intake runners are connected by one side of the intake.
Cylinders 1,7,6 & 4 are the other chamber.
So the bank 2 related issue is probably something after the cylinders.
My guess would be a bank 2 cracked exhaust manifold, loose pipe connection, bad O2 sensor/heater or partially clogged cat.
There's not much else after the cylinders.

 

Good idea...

Find someone who knows how the system is supposed to work. You don't want a code reader/parts hanger, you could do that yourself.

 

Thank you folks. Your responses are most helpful and I appreciate it. A cracked exhaust manifold did not occur to me. The O2 sensor was my first guess as it is unique to that bank. I will test for both before heading off to a diagnostic.

 

I forgot to include the "2 or 3 miles" is interesting.
I think the PCM is in Open Loop control mode until the O2 sensors are heated up, then it goes into Closed Loop mode.
I think this happens at around 1.5-2 mins after start-up.
Might be related.

A cracked manifold or loose exhaust pipe would be quite audible.
I had a loose pipe causing a P0171 about 1.5 min after start-up.
While researching I saw in our 2003 Exped 5.4L there was a fuse for the O2 sensor heaters.
I don't see one in the 1999 F250 Owners Manual.
Probably not that anyway because eventually the O2 sensor would heat up from the hot exhaust and run normal.

How many miles on the vehicle?
The recommended change interval for O2 sensors is 100k.
Our 2003 has 161k with the original sensors and still runs great getting 15 mpg freeway.
If you're pushing 200K maybe just change the bank 2 sensors and see what happens.
Motorcraft O2 sensors are around $25.

 

I would NOT blindly replace any O2 sensors (or anything else, for that matter). There is a specific reason I recommended finding someone who understands HOW IT WORKS, that is to prevent wasting time and money hanging parts.

If the problem only occurs when the engine management is switched from open to closed loop, then it's going to be necessary to look at all the PCM inputs that are used during closed loop operation. A comparison to measured vs reference values for each of those sensors needs to be done to see anything is skewed enough to make the engine misbehave. There are a ton of potential suspects, the list needs to be narrowed down logically, not by guessing.

It would also help to know if this is an OBD1 or OBDII vehicle, the OP would need to look at the label on the underside of the hood, at a minimum. The simpler OBD1 system is limited in its data available for diagnostics, it also has fewer sensors and emissions subsystems.

 

So the symptoms point in the direction of an O2 sensor.
If, like I said, the vehicle is getting close to 200k or twice the service life of the O2 sensor to me it makes sense to try a simple test of swapping one part.
Worst case you have a spare O2 that will probably need to be used soon anyway, best case it fixes the problem.
Should we leave our spark plugs in until they die, never change the boots until a misfire code is set, only change the coolant every 15 years?
I agree diagnostic equipment is needed to find the actual problem, but if it is OBD1 it might not help as much.
I'm learning how to use mine.
Do you have any info on what changes in engine management when it switches from open loop to closed loop?
I haven't found anything on line, yet.

 

The symptoms and available data point nowhere.

 

Just for review are these the code descriptions you are getting?
P0174 - System Too Lean (Bank 2)
P1150 - Lack Of HO2S21 Switch - Adaptive Fuel At Limit - Bank 2
Lack of Upstream Heated Oxygen Sensor Switch Adaptive Fuel Limit Bank 2
Lack of Upstream Heated Oxygen Sensor Switch Adaptive Fuel Limit Bank 2
Lack of Upstream Heated Oxygen Sensor Switch Adaptive Fuel Limit Bank 2
P1151 - Lack Of HO2S21 Switch - Sensor Indicates Lean - Bank 2
P0305 - Cylinder #5 misfire detected
P0307 - Cylinder #7 misfire detected
P0308 - Cylinder #8 misfire detected
Have you cleared the codes and have any/all come back?
How consistent is this set of codes?
While cylinders #5, #7 and #8 are all on Bank 2, #7 is not connected to the same chamber in the lower intake manifold with #5 & #8. The common point for #7 is in the Bank 2 exhaust manifold.

Found some info on what can cause a P1151 -

A code P1151 may mean that one or more of the following has happened:
Electrical:
Short to VPWR in the harness or HO2S
Water in the harness connector
Open/shorted HO2S circuit
Corrosion or poor mating terminals and wiring
Damaged HO2S
Damaged PCM
Fuel System:
Excessive fuel pressure
Leaking/contaminated fuel injectors
Leaking fuel pressure regulator
Low fuel pressure or running out of fuel
Vapor recovery system
Induction System:
Air leaks after the MAF
Vacuum Leaks
PCV system:
Improperly seated engine oil dipstick
EGR System:
Leaking gasket
Stuck EGR valve
Leaking diaphragm or EVR
Base Engine:
Oil overfill
Cam Timing
Cylinder compression
Exhaust leaks before or near the HO2S(s)

 

this very well could be more than one problem they are just happening at once. swap the cops over to different cylinders and see if the miss follows the change simple and free to do that. next thing is when a pcm is in open loop it is going to be doing several things one the 02 sensors are not going to be doing much because the pcm is trying to get the engine to operating temp and is checking this by the coolant temp sender which is telling the pcm to run more the rich side to help the engine get to temp your heated 02 sensors are not working at this point just the non heated 02 sensors. to keep the pcm from throwing to much fuel to the engine.
so to me i would be leaning more towards the heated 02 sensors for the bank 2 lean. next i would do a halo test on the oil remove the dip stick get a paper towel and let a couple of drops fall onto the paper towel the oil and fuel do not mix and will separate from each other that will let you know if you have a bad injector.
next get a can of starting fluid and while the engine is running spray around your intake and all vacuum lines to see if there is a leak somewhere listen for idle change it will idle higher if it has a leak somewhere.
and remember to look at problems one at a time do not bog yourslef down with trying to make the problems related when they may not be let diagnostic procedures tell you if they are one in the same problem or one problem by itself