P0401 EGR Code, Buzzing Charcoal Canisters, and No Starts... FML.

Back in Feb, I made this post: http://www.tacomaworld.com/forum/technical-chat/73112-possible-egr-valve-need-advice.html After closer inspection, I found the EGR itself to be ok, but the brand new gasket had failed. It was rough going in, and I was working blind so I may have eff'd it up a bit in the process. Anyway, after installing another new gasket, and reseting the ECU, the truck ran fine and no more CEL.

...for about 9 months. Now the dreaded CEL is back again with the 0401 EGR Insufficient Flow Code. In addition to that, the truck is hard to start. The battery that was in there was about 3 years old, so I went ahead and replaced it, and the new one is doing the same thing. No battery light, but one thing I have noticed is the Evap/Carbon/Charcoal Canister Contraption behind the battery on the Drivers side fender buzzes. Even after the truck is off. I haven't verified that it stays on indefinitely, but right now the truck has been off for three hours, I just checked it again, and it's still buzzing. Its a quick little 1-1 1/2 second buzz (like air through a diaphragm), with about 10-15 seconds in between each "buzz".

Is this "buzzing" normal? Could it be draining the battery?

 

Just noticed another fun fact. The radio has started powering off when the headlights are turned on. It comes back on a few seconds later, but if you turn on the high beams, it stays off. I haven't pulled it out to see (the previous owner had it professionally installed), but I would imagine the head unit is sharing a 12v switched power source with the headlight switch, but why would this only happen now after over 8 years. I imagine this has to be related to the slow start issue. Any ideas?