2004 Dodge Ram 1500 4.7 Auto Trans. 85K miles P0440 and P0441 codes. A few months ago I got the P0440 code. I replaced the gas cap with an after market one and cleared the code. It ran great for a while then I had problems one day with it dyeing when I let up on the gas to turn the corner a few times. I had my son that works at a car dealership to order me a Mopar OEM one and that cured the dyeing. Things were great for many months as I only drive about 4K a year and after I got the code a lot of it was in the winter. I did notice that I would get the 440 right after I filled up with gas and then run it down to 3/4 tank and then not drive for a couple of days and the Texas temps would get in to 100's. Two days ago I went to go somewhere and I got the 441 code on startup and yes the temps were in the 80's and the tank was down to 3/4 and it had been a couple of days since I drove it. I live on SS so not a lot of $ so I need to fix it cheap. Any suggestions would help I am sure just don't want to throwing parts at it. It is like the gas gets hot and causes more vapors when it sits then it fires off the code when I use it, The truck runs good but suck at gas mileage but it always has. I will post some of my OBD-II test sheets if that is allowed.

 

Check underneath the truck right under the driver side door between the frame rails. There should be a black plastic cylinder shaped thing(filter?) and next to it a black box looking thing. Sorry don't know what theyre actually called but its part of the evaporator system. The hoses connected to them, 2 I think, maybe cracked or broken. I had one that was craked and disconnected. Not sure if your truck has torsion bars but its right behind the bars on my truck. 03 5.7 hemi