Sorry, got busy at work, had to do what they pay me to do for the rest of the afternoon, fancy that.
You do have to remove the intake plenum, at least most of the way. The throttle body will stay attached to the plenum. The first thing to do is take a bunch of digital photos of the top of the motor, cover every angle you can. These will come in very handy.
I tried to do this with the partial removal method and found it was just easier to disconnect everything on the passenger side of the plenum and hook it back up later. If you take close up photos of the vacuum lines you will be fine. Most are numbered, nice touch by the Toyota engineers, so the pictures will show you where to put them back. A few need to be labeled, make sure you do that when in doubt.
You will need to drain the radiator, at least part way. The throttle body has coolant flowing through it to warm it up faster, two connections, down low, front and back. Also, there is a coolant pipe that runs under the plenum to the rear of the motor. This is a hard line that has rubber lines on either end. This path will need to be broken also. Most of the work is in labeling and taking photos. It only takes about 1/2 hour to get the plenum off.
Once the plenum is out of the way there is one thing you really need to be careful about. The dreaded and much maligned Knock Sensor Wire <img src="/forums/images/graemlins/evil.gif" alt="" />...Duh, duh, duh....
On the drivers side of the intake manifold there is a wire that drops off the wire harness by the #6 fuel injector and dives down in a little notch in the manifold. It goes underneath the manifold, where there is a convenient air space between the top of the block and the bottom of the intake manifold. In this cavern of doom resides the knock sensor, cooking away for years on end in the bowels of the engine. The connecting wire is a co-axial wire that cooks along with the sensor and becomes very brittle over time. If you play around with it, you might crack the wire and cause a failed connection. Then, you put it back together and you get an engine code for the knock sensor. <img src="/forums/images/graemlins/scared.gif" alt="" /> Then you get the pleasure of taking the plenum back off, removing the intake manifold, replacing the wire and the senor (you are in there, so why not), and then deciding if you should have the injectors serviced, the manifold tanked/blasted, etc, etc.
So, locate that connecting wire (the wire can be removed from the harness, so, Toyota knew it was a service item) and make sure you treat it kindly.
Other than that, just remove the valve cover bolts, remove the valve covers, clean everything up, and then re-install. Make sure you put RTV or TRS or some kind of sealant in the corners where the FSM recommends. A little dab will do ya on that stuff, don't put too much. As indicated above, follow the FSM tightening procedure.
While you are in there, you might want to check the valve clearances and do a valve adjustment at the same time, if it is due for an adjustment. There is one tool that is recommended that comes in handy. It is the tool that holds the bucket down after your compress the valve assembly. The other tool, the little plier like thing is useless. Use an allen key to compress the bucket/spring assembly. A small flat blade screw driver and a magnet wand work great to get the shim out to measure it, if you have to remove it (only if the clearance is out of spec).
As for gaskets, I have been using the FelPro blue valve cover gaskets. They seem to work really well, no leaks 5k miles. It would be best to get a new EGR gasket, but, if the one that is on there comes off in one piece, it will probably do the job when putting it back on.
Let me know if you run into any problems, I have lots of pics stored of mine. I have a 15 month old at home, so I spend a lot of time around the house lately....
Mike
