Hello everyone. I'm having a problem with my 06 f250 5.4L gas.

First some history - I bought this f250 for a low price but with a lot of problems including the camshaft phaser problem and a bad computer. I've replaced the camshaft phasers, chain, chain guides, phaser solenoids, computer, oil pump, power steering pump, some spark plugs and some coils. Since the repairs, it has been running fine.

Recently, it has become very cold in Minnesota. This has been the first episode of severe cold this winter. It has hit -20F in the night time here. The other night when it was probably -05 or -10, my business partner was driving the truck and it was fine when suddenly it started struggling and almost stalling out.

I went over there to take a look at it and it indeed was stalling out when the vehicle was first started. It runs really rough with a lot of hesitation. It sounds like it's not firing on all cylinders and it's very erratic. If I give it some gas the engine smooths out a lot. It is having the most trouble on idle.

I took some readings from the computer and here are the error codes:

P0349 camshaft positions sensor "a" circuit intermittent bank 2
p0430 catalyst system efficiency below threshold (bank 2) (this is an old code and has been there all year)

pending error codes:
p0022 "a" camshaft position - timing over retarded (bank 2)
p0171 system too lean bank 1
p0305 cylinder 5 misfire detected
p0345 camshaft position sensor "1" circuit (bank 2)
p2195 o2 sensor signal stuck lean bank1 sensor 1
p2198 o2 sensor signal stuck rich bank2 sensor 1

I reset the computer and started the car and it ran smooth for about a minute but then the stalling problem returned.

I took out the camshaft #2 sensor and there was metal dust filled gunk on the tip and sides so I cleaned it off. This resolved the camshaft related error codes but the stalling problem was still there.

I ran the mode 6 diagnostics using torque on my phone and it did show that cylinder 5 was misfiring a lot. I replaced the spark plug there and that mostly eliminated the misfiring on cylinder 5. However, cylinder 7 started misfiring a now. I replaced the coil on that cylinder but that had no effect. I'm now getting an error code for P0300 random cylinder misfiring.

I tried unplugging the mass air flow sensor because I read that some cars can run without it and if it's broken unplugging it is a good way to test it. Doing this had no effect.

So, does anyone have any ideas what is wrong at this point?

 

Wow, never seen so many codes at one time. The only 1 I can comment on is P0430. Sounds like your cat is getting plugged. Too much engine back pressure at this point.

 

Cats are not plugged. I have taken that part of the exhaust off and visually inspected them before. However, the cats are burned out. The persistent misfire I had on the vehicle before caused there to be a lot of unburned gas getting to the act which caused all the palladium in the cat to be used up. There was no visible melting though. This is a common problem for any vehicle with a persistent misfire that is not resolved.

 

a misfire.. low fuel. or high fuel.. not just coil and plug. for one cylinder. dirty injector. bad injector. bad wiring for injector..bad computer chip for that channel.

random misfire.. could be Low fuel pressure from pump.

bank 2 sensor "Rich".. could be a leaking fuel injector..but not to cause a misfire.. or can.

stalling at idle.. check and see if you have an Idle Air Control valve.. could be dirty or bad.

address each code .. One at a time...

 

There is not IAC valve - it's drive by wire throttle.

Addressing the issues one at a time is usually good advice. However, in this case all those pending faults happened simultaneously. They're really just side effects of the singular cause of this issue. Addressing them individually will not work.

 

My first thought was that you have water in your fuel. At -20, you have ice crystals in your fuel. Ice crystals don't go through fuel filters very well.

Is it running any better now that them temps are in the low 30s?

 

without having Live Reads of the sensors.. how are you going to solve all from one problem.

Are you Sure the computer is healthy..?

Best of Luck. done here.

 

No it's running worse. I was expecting it to run better but that's not the case.

 

Update - I went to take a look at it again today. I looked at the fuel pump driver and it didn't look horrible. It's hard to tell for sure since the the spare tire was in the way.

The cylinder 5 misfire came back. I replaced the coil on it but that had no effect.

I tried cleaning the throttle body. I took off the air filter and sprayed b12 in. Now when I did this, the engine smoothed out and definitely got stronger. Is this supposed to happen? The spray is flammable no doubt but the engine should be in a choked state when starting cold so it shouldn't benefit from more fuel should it? Is this an indication that the fuel pump is failed? I should also mention that the fuel level signal from the fuel pump failed several months ago. Maybe that is related.

Anyway it's so bad now I can't even drive it out of the parking lot. The problem has been getting worse every day.

 

Have you checked fuel pressure?

 

my first post. reread it. or take it to a professional.. I was one.

try line 2.

 

Well I took it into a shop shortly after my last post. I had to call them up today because they seem to have totally forgotten about my truck.

They said that they wanted permission to take apart the whole top of the engine to check for more problems. They already checked a bunch of things including the spark plugs and coils and fuel pressure and they didn't find any problems there. Now they suspect a burnt valve or bad timing chain. The timing chain was already replaced last year.

Even if it did have a burnt valve, the truck should be able to start and run even i
f it would be very rough. Right now it doesn't even start without stalling right away.

Last year the timing system was actually messed up and I had to change the timing chain, phasers, and chain guide. The phasers were literally coming apart at the seams then and the chain guide had already had bits and pieces of it that had fallen off. You could hear a problem with timing very easily but the engine still started up and stayed running fine even though it was very rough and had little power. Also, when the problem this time was quite so severe, I could start it up and keep it running by applying gas and the engine felt and sounded smooth. Given that the engine sounded fine then even though it was stalling on idle, I don't see how it could have a severe timing problem keeping it from running now.

The symptoms point to no fuel but they already checked for fuel pressure they said. The only thing I can think of is a bad computer like Chuck said or maybe a bad mass air flow sensor. I know a lot of cars won't let you run without sensible sensor data coming in from the mass air flow sensor so maybe that is it? I haven't checked that sensor but when I was monitoring it with the OBD reader I checked the intake air volume was steady while it was at idle.

Does anyone else have any ideas? It's way too expensive to just replace the entire engine.

 

Why not do a compression test on cylinders 5 & 7?

 

You can also have good fuel pressure but bad injectors, like Chuck said. Swap injectors and see if the misfire moves.

 

I'd be very concerned about a repair shop that wanted to tear down the top of an engine before doing a basic compression test.