My 2007 with 5.7

Hey folks,
Just thinking about my Tundra while out looking at them with our son. Mine is a 5.7 with 150,000 miles in a 2007 and when I start it up cold or warmed up it idles REALLY high, kicks down some in a minute or two but is still high. It is worse in the cold than it is when warmed up but it is still high idle. The reason I ask is we looked at a 2010 Limited Platinum w/5.7 today that hasn't been started in 9 days and it's 50 degrees here. When my son cranked it up it didn't rev real high and made no bad noises. No ticking, knocking and idled just like it should, a little high but normal. What could it be in mine that makes it rev so high????
And another Q, the charcoal canister needs replacing, what's the best source for one? Do I need to buy a Toyota brand at the $700 or are aftermarket ones good?
My backup camera has a tiny screen on the headliner, not in the mirror. But it doesn't work and I would like it to. IS it factory if the monitor is in the headliner not the mirror? THANKS

 

Clean your throttle body and MAF.