Lexmex

This is the bolt.

Note: This is the second time that I have personally removed the throttle body and I won't be putting this bolt back on, nor the following one. I have found based on personal experience that the 3 bolts on the throttle body are sufficient, but in anyone's else case this is a personal decision.

Lexmex

The next bolt is a major PITA.

It is a 12mm bolt that you can feel if you put your hand on the backside. To locate it, feel immediately below this point and behind the throttle body and you will feel a bolt. This bolt is supposedly held together buy a nut on the other side, however last time I did this I saw no such nut and the bolt was loose. I did have my spark plugs replaced at Lexus several years ago, but not sure what method they used. Again, check to see by feeling around if there is a nut on the back of the bolt (you might hear a clink of it dropping).

If there is one bolt which I ABSOLUTELY will not put back on, this one is it.

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I recommend as with the other screw to install the extension piece first. Remember this one is a 12mm, unlike the other one which as a 10mm.

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Now it won't sit flush on the bolt itself. That is because there is a metal bar immediately above that prevents this. Instead you have to place the extension on it so that it is like at an angle as shown in this example.

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Then attach the ratchet. (note photo is of extension).

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Here is the extension in place on the back before ratchet is attached.

Note that metal bar just above that I was talking about.

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Then attach the ratchet.

This will take some patience to slowly, but surely get that bolt off.

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Here is that 12mm bolt.

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After that murderous experience, you will now be able to pull the throttle body further apart from the intake manifold as shown.

Now about a month ago I did this and cleaned out the throttle body using carb cleaner and also took a coat hanger, wrapped it with some gauze and tape and proceeded to ram it through these two holes shown here and boy was it ever yucky. The throttle body itself was still very much clean a month later this time, but still another reason to add the oil catch can and improve combustion.

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Another shot of the area.

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Another shot of the area as seen through the back of the throttle body itself. Still very much clean. If you note on the bottom center you can see the hole where that 12mm bolt went through.

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A little closer view into the throttle body. This horizontal piece you see here on the right side is the second section of throttle butterfiles. If you pull the accelerator cord, this piece will actually fold vertically. Some people who do performance modifications actually remove this second butterfly to improve air flow (granted it does go vertically, but not fast enough, as you want the air to go smooth through the throttle body immediately after the first set of butterflies opens (as you see at the front of the throttle body) and not have to wait until this piece goes perfectly vertical).

You can see part of the front butterfly of one side in the extreme lower right corner.

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Gasket between the throttle body and intake manifold.

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Now at the bottom of this photo are 2 holes. The top one is for the 12mm bolt and the bottom one is for the 10mm bolt.

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Again, whether you put the 10mm and 12mm bolts back in is up to you. For me it was painful and I haven't noticed anything negative as a result. I have linked this thread to the spark plug thread as of now.