2001 Pathfinder with P1491 code Vacuum Valve cut bypass

[zpmada]

Hi all,

I have a 2001 Pathfinder that I am trying to make compliant for a friend with a check engine light. The car originally had a few codes due to the idle control valve. I took the upper intake off, replaced those gaskets and the idle control valve. I also replaced the PCV valve (aftermarket brand) as the old one was blocked.

Now I am left with a P1491 code. I am not sure if I had this code before I removed the upper intake manifold, or if it came as a result of removing the upper intake manifold. What can I check to rule out the upper intake manifold?

Could a defected PCV valve cause the P1491? (I sure hope not as that valve is burried under the upper intake manifold).

Here is what I have done so far, with no success:

Replaced Vacuum cut solenoid switch (Genuine Nissan Brand)
Replaced Vacuum bypass valve (Dorman Brand)

What else is there? I noticed when I removed the hoses on the vacuum cut solenoid switch, it was a little moist with fuel. Is this normal, or do I have to dish out $200 on a new charcoal canister? I'd had to keep throwing money at it without knowing for sure what the problem is.

Thank you!

Edited September 29, 2014 by zpmada