My 2003 Expedition just started running like crap...missing and skipping at idle and while running. It had 157K miles. Plugs and all maintenance done at the recommended mileage. PO 442 usually says gas cap, vacuum leak or bad charcoal canister. The gas smell is over powering at times. Checked the fuel filer and it is dry.....where did those $!@#% engineers hide the charcoal evap canister? I can't find it to save my life.

 

Whenever I hear the words vacuum leak the first thing I always think of is the notorious PCV hose that goes from the pass side valve cover to the back of the throttle body. They are infamous for coming apart with age.

Take a look at that for giggles.

 

The charcoal cannister is located in the driver side rear of the truck near the spare tire. It is most likely not the problem as the vacuum elbow at the absolute rear of the intake is most likely the culprit. It has to be a pretty bad leak for the amount of fumes you describe as getting into the cabin.
My experience has been that the biggest problem with the charcoal cannister is squirrels, They seem to like the taste of the insulation on just about any exposed wires on Ford trucks. They have eaten the spark plug wires, trailer connection, and the cannister wires on 4 of our Ford products.
I have found that wiping Tobasco Sauce on all of the exposed wires under the truck and the plug wires have stopped the problem, for now at least.

 

The drive-ability symptoms and the P0442 fault code are likely two separate problems.




Watch out for Louisiana squirrels! They might like Tabasco.

 

Thanks for the input guys. The reason I am confused is the Chilton manual says the canister is rectangular on the truck and cylinderical on the Expedition and does not show location. I think I found it on the back frame rail right above the spare tire...however it is square. Now here is the weird part....a hose is leaving that canister and is zip tied up to the gas filler neck but is just suspended there. There is a connector that looks like a snap on connector but it doesn't plug into the filler neck like it looks like it should to recirculate fumes. Does anyone have an illustrated parts breakdown pic of the gas tank and filler neck? Also the outside neck has what looks like an plastic lip that has cracked and therefore not allowing the cap to seal. Looks like I need to replace the filler neck.

I replaced in infamous vacuum line at the back of the intake several months ago. It does appear as though I have multiple issues. Thanks for any insight and help...this is really the first semi serious problem I've had with the Expedition in 10 years.

 

That open hose is the inlet to the vent.

Fix the cracked filler neck, it's going to cause your fault code symptom.

 

Sorry for the confusion on my part...is the hose supposed to be like that? Or should it plug into the filler neck assembly somewhere?

 

Be careful not to damage the filler hose and/or neck. They are probably not available any more and they are pretty expensive from Ford.
My cannister is against the driver side rear frame, about 6" diameter with fuel vapor hoses and a sensor with, I think. 4 wires in the harness.