Hey everyone I'm looking for a fix for this; I can put my dial on vent and it will blow out the vent until I step on the gas, then it switches to defrost. The truck still gets nice and warm so its really no big deal just odd. I can stop at a stop sign and put the dial on floor, and it will blow on the floor until I step on the gas pedal and then it switches to defrost until I stop for some other reason then it will return to floor until I step on the gas pedal. This truck is a 2006 so I'm still working out the minor bugs that came with it. The other problem I'm having is can't pump gas in it, well I can but it takes forever because the nozzle shuts off every three to five cents. I shoved that thing in, up and down in and out, upside down and sideways. Well I'll tackle that thing when it gets warmer outside, right now brrrr!

 

You have a vacuum leak that's what's causing the air to switch to the defrost vents that is the default position incase of a leak very common start with the vaccum lines at the hubs if 4x4 thats the one most common leak points in the system. Since you're pumping gas in it though you don't say which motor you have the problem your having is also very common on either of the 2 choices clogged vapor canister the hose may just need clearing out or the whole canister may need to be replaced. Believe they relocated them under the truck near the spare tire and it will clog up with dust and dirt much easier under there than the previous years they moved it in the 05 redesign.

 

Thanks for the reply Mike189677. In a way I am glad they are both common issues, that being so someone with knowledge can steer me in the right direction. I found an OLD thread pertaining to the pumping gas situation last night while I was here on this forum, they mentioned the same procedures to correct the issue. The motor is a 5.4l and it is a 4x4. So, a major vacuum line could be cracked broken or unplugged by the (hub?)

 

Mike is correct, you have a vacuum leak. The vacuum pump and vacuum tank are on the passenger side, near the battery, if you have ESOF the vac line also runs to the hubs, if you have manual 4X4 they do not, the leak however is probably close to the pump or tank, there is also a vacuum solenoid close to them that could also leak, the lines to the hubs only get a vacuum pulse when switched into or out of 4X4, they could be bad but are not causing your immediate problem.

 

Gas engines create there own vaccum unlike diesels they don't have a vaccum pump but the solenoid that feeds the hubs is still on the passenger side follow the lines from the hubs up looking for damage or disconnection

 

Now I have enough info to tackle this repair. Thanks guys!

 

Mike is correct again, I neglected the fact that you have a gasser.

 

Pickup a mityvac, then start unplugging vacuum lines 1 by 1. Use the mity vac to draw vacuum in each line. If the line holds vacuum, move to the next one until you find the one that leaks. Be sure to check the vacuum canister too. Sometimes, immediately after shutting the engine down, if you listen carefully you may hear it.

 

TonOfun06,
I would think if your ESOF switch is in the 2WD your vacuum leak would before the PVH Valve since the PVH Valve doesn't cycle until the ESOF switch is in 4WD. I would cap the vacuum line before the PVH Valve and see if that changes anything before digging too deep into your other vacuum lines. When checking your Hub Lock vacuum lines be sure to check the plastic line from the PVH Valve where it runs down the frame next to the starter & exhaust manifold. My vacuum line was melted in two at the frame where it runs close to the exhaust manifold - mine's the 6.8L though. Also in one of the threads I looked at stated to replace the rubber vacuum hose with 3/16" black irrigation tubing since it's UV protected this is what I did but I still had to run rubber hose to the spindle because the irrigation tubing would kink when making full turns.

For the carbon canister located above the spare tire assembly I went cheap and took it to my work to back blow the canister. After disconnecting the hoses I taped 2 separate air nozzles - one to the filter end and one to the carbon end, zip tied the valves wide open and let it run for at least 6 hours straight. I'm now able to lock the gas pump handle full open and walk away and it will fill my truck with gas. At first I just back blew the air filter part and the carbon part with air from my home compressor - that helped but didn't cure the slow fill problem.

If you plan on purchasing a new carbon canister assembly the best price I found was through RockAuto.com About $135.00 if I remember correctly. It's listed as a Vapor Canister. Here's the link:
2006 FORD F-250 SUPER DUTY 5.4L V8 Vapor Canister | RockAuto

 

Not much progress since its been nasty cold. I did take advice and picked up a vacuum tester for this job. Charcoal canister is next on the list of items to check.

 

Did you check the FIRST things on the list, like the PVH solenoid (!), the vacuum lines near the battery, vacuum line through the dash, vacuum lines to the HVAC control head, etc? All are FAR more common that are leaks in the charcoal canister/EVAP system which can only cause your primary symptom during the time the purge solenoid is on? Same for the vacuum lines to the hub-locks - they can only cause your symptom during the brief time the PVH solenoid is energized.

Check the common stuff first, saves a lot of wasted troubleshooting time.

Now, concerns with the canister can affect your second symptom regarding fueling, but the two problems are unlikely to have a single cause. Threat them separately for now.

 

Does my gasser need to be running to do these tests? 5.4L
I did plug the vacuum tester into the left and right hubs and they held 5 inHg vac for several minutes.

 

If you're using the hand-held, then no. It supplies the vacuum for testing.

 

Found the vacuum leak. it was a hose clamped to a metal pipe close to the vacuum booster that went to the vacuum booster. The clamp crumbled in my hand, visually it looked fine. The same thing just happened with a radiator hose clamp. I replaced ALL hose clamps, a little late though because the top radiator hose clamp cut loose and blasted everything under the hood with anti freeze. Now I have electrical problems; TAC PCM when it rains it pours.

 

OKAY so I finally got it down to two error codes P0171 and P0174 and after reviewing my freeze data determined the air leak is the problem, and it is a big one. Also the water pump pipe is all rotted out too. I don't know if I can cut it and add gas line or buy a new one? The new intake will be here Thursday 15th