I'm also having a problems with P0011. I just recently got my car back from a rallispec shortblock swap along with refurbished heads with Kelford cams, new valves, retainers, springs etc.
When I first got the car back I was throwing P0011 & P0021. Got the car home, changed the oil, pulled both AVCS solenoids, inspect, cleaned and tested them, they worked fine. Put them back in reset the ECU, the codes did not come back immediately like they did the first time i just reset the ECU without doing anything.
A couple days later P0011 pops up again, but nothing else. I left it alone and before the day was out the P0011 disappeared. So for the past week and 1/2 P0011 seems to be coming and going randomly as it pleases.
Now i called the mechanic who did the swap for me, he told me he pulled all the screens out of my lines to prevent such a problem. The only thing I can think of is my passenger side AVCS solenoid is on it's way out, and i'm waiting to get ahold of a different solenoid to give it a shot.
My idle does occasionally suck, usually when the car is warmed up and i've thrown the code. I've also noticed that under normal circumstances my oil pressure jumps up near 90psi under any sort of throttle, however when i'm throwing the code my oil pressure doesn't like to go above 70 and the car feels like a total dog...