p0441 code in an 03 dodge ram 1500 p/u

I have a 2003 dodge ram 1500 with a 4.7L engine. My check engine light came on with a p0441 code. I checked the gas cap and its okay. I am a diesel mechanic, but have no experience on these trucks. If anyone could point me in the right direction I would really appreciate it. The truck seems to idle rough in gear, but otherwise runs good. It has recently had a tune up which helped some, but now i keep getting this code. I suspect that the purge solenoid may be faulty, but its too expensive to keep guessing as to what the problem may be. If anyone has any advice I would love to hear it.

doubtful purge solenoid! leak detection pump more likely

Thanks for the info. Is there any way to test the ldp? I got a manual for the truck, but it isnt very clear abbout the ldp. Thanks again.

To test it you have to actuate the switch contacts internal to it! they tend to stick, a scanner that has bi-lateral commands would verify whether it will respond or not!