I've been having this problem for many years and the last 2 months I have spent a lot of time trying to fix the problem.
I have replaces the purge valve, the solenoid, and now the first 3" of line going into the valve and then from the valve to the solenoid.
the Valve is facing the right direction since there is pretty much only one way it goes on. and I've felt as much of the other lines as I could and can't feel any cracks or ware or anything.
Now I am out of options.

 

unhook the hose at both ends and see if you can blow thew it without problem. then plug one end and do the same and see if it leaks. have you changed your gas cap? checked the relief valve to see if its stuck? checked the evap tank to see if its holding together and not full of gas? sometimes the coal in it will come apart and plug things up. also look over connection at the solenoid

 

Alright I will start from the top, I've blown threw the hoses no clog, and don't quite under stand on how to check for leaks on blowing with one end hooked up? Which end do I hook up and blow on? I have already changed the gas cap, just cleaned the relief valve, it was clocked and fixed the problem for about 4 days then the light just came on today, evap tank is great, and when I changed the actual valve, I changed all the hoses going to the solenoid, this is the problem I'm having, is there a purge valve flow since that I can check the conjinuity on? To see maybe if its bad thats if there is even one?

 

pick up a new relief valve. it sounds like it worked for a while and failed to me. i was sayin to unhook both ends and plug one end. then blow, if nothing goes through you know the hose is holding air. was there coal in the line or anything you replaced?

 

Well the short lines that go into both ends of the valve and the single short line that goes into the selinoid I replaced because they were super wore out but now for the rest of the lines that go to the tank, I don.t know how to even get to them yet to take them off let alone to blow in them or even replace them, and I will go pick up a relief valve this weekend and change that, when I took it apart it was really filled with dirt, could have dirt gotten back into the line? Which I don't see how it could?

 

the relief valve has a spring loaded check valve in it that will realease pressure if it gets to high. its on the end of a hose sorta wraped up next to the fuel tank. if it gets stuck open or closed you should get a evap code. the evap hose goes all the way back to the pressure control valve. have you seen this https://camaroforums.com/forum/lt1-l...-system-51219/

 

Ok so the code that comes up everytime is, P0441B, evap. Ctrl bad purge flow. If this helps

 

Alright so update on the proble, I've done everything craby told me and the light came on last night while driving around, but I didn't found out there is an evap valve in the engine compartment, could this be a problem in any way?

 

yep if you can blow through it both ways when its not plugged in its no good. not sure where its at on a 3.8, lt1 its on the passenger side of intake. follow the evap hose that goes to the tank up to motor and see were it goes. under hood it should go to evap solonoid.

 

yeah it is in the same spot. it have a little description of it all under the hood, realized this when I was doing the new CORRECT C.A.I. and new water pump.