Have a 2003 dakota v6 and was informed by a friend that works at a dealer of issue concernig this . reciently my check engine light came on and was told when codes where checked to look under drivers side of truck along frame to the charcoal box . the center hose that goes into the box has a tendancy to crack at the end going into the box cut about an inch off of the hose if able to do so heat the hose up with a head gun or other means reconect the hose and disconnect the battery for about 10 min for computer to reset and wait if after a week light dosent come on your fixed if it dose your screwed

Code is purge flow sensor , locateded under hood on drivers side ,next to brake resavore, cost is about 48.00 napa ,hoses are tight take your time when removing .
also check and or replace gas cap with new one 11.00 napa
steve

I have a 2003 Dodge Dakota 4.7L V-8 with the same problem (code 0442) which is a small Emissions leak, where a code 0441 is a larger vacuum leak. The problem is leaking vacuum hoses.

I replaced the gas cap, problem remained. After detaching the battery cable, thereby resetting the error, the dash light (code 0442) error would return in about 50 miles. The problem is the Natural Vacuum Leak Detection (NVLD) device. The NVLD is a device that detects any leaks in emissions system by monitoring vacuum pressure. As your engine warms up the difference in temperature creates a vacuum pressure change, if there is a leak, the vacuum pressure change is lost and the computer registers a fault.

My problem is with leaks in the vacuum hosing. For the 2003 Dakotahe NVLD is primarily made of two parts; an electical sending unit (behind the battery) and a vacuum chamber attached to the frame on the driver's side halfway between the engine and the gas tank. I replaced the rudder vacuum hose between the electical sending unit and the intake manifold ( less then $5.00 worth of hose) and another hose (special order) that attached to the vacuum canister (I think I paid $16.00).

This is a fix that can be accomplished by anyone that does the minimum level of wrenching. With mine truck I had to be careful of the 1/4" hard plastic vacuum lines that are used for most of the run between the sending unit and vacuum canister (the rudder hoses are used at both ends of the hard plastic lines.

Good luck.

Had similar problem, turns out I replaced with wrong style gas cap. If you have a 1/4 turn cap it must be replaced with another 1/4 turn cap and not one that screws on. Hope this helps.