My check engine light is on in my 2004 f 250 5.4 for a possibly bad purge valve. The loose gas cap light has also been coming on and off for no apparent reason. Is there anyway the two could be related? The code i got was PO443 which if i remember right indicates a leak in the emissions system. any response would be appreciated

 

Absolutely can and probably is related. I had this same problem and found that the vent solenoid had fallen off. I do snowplowing so I guess all the bouncing and banging was the cause, might be worth a look.

 

There's a loose gas cap light?

P0443 is Evaporative Emission Control System Purge Control Valve Circuit


EDIT: I checked the manual at

http://www.analogstereo.com/pdf/om/f...anual_2004.pdf

and yes, there is a Check fuel cap light!

 

Yes the loose gas cap can cause a CEL. What I want to know is how a loose gas cap is so bad when Ford is coming out with their No Gas Cap models.

Any one know how a flapper valve type set up would be better than a loose cap?