edbro

Wow, that's great. Thank you.

1. Isn't there a coolant line that runs through the throttle body?
2. Can the gasket be reused or should we order a new one if planning to remove the TB?
3. How much space does this give us? Can the plugs be easily gotten to now?

Lexmex

1. Yes there is, but my objective here wasn't to have everyone take off the entire throttle body, just to be able to get at it so that one can get at the rear plugs. You can actually get at it with carb cleaner and place a plastic bag below it to catch the drip.s
2. You can reuse the gasket
3. Yes, you can get at them much easier. However keep in mind that the intake manifold that is still there may not make it entirely easier. However, keep in mind as I said in the spark plugs DIY that the hardest coil/plug to attack was the one in the rear right.

TunedRX300

Great DIY, I will come back to this thread when I clean the IACV and change spark plugs. The rear right coil will also get replaced for preventative measure because I don't want a bad coil to foul up my catalytic convertor.

mandyfig

Another well done piece. What camera do you use, they take good pics.

Lexmex

Canon A610, got a good mark in Consumer Reports along with the A620 that offers more pixels.

TunedRX300

Next time you take this gasket off, you can replace it with a non-metal one to isolate heat from the engine block from transferring to the throttle body.
Cooler intake means more power, not as much gain as the isolating spacer between intake manifold and engine but every bit counts.

salimshah

You are right .... with thermal insulator the rate of change of temprature would be slower, but once the E block reaches stable temp, and given long enough time the other side will will match the temp of the E block

Salim

TunedRX300

I like your reasoning, the other theory is phenolic spacers make the "heat sink" smaller and the heat that is not transferred will be taken out by the cooling system. It may be triggered by opening the thermostat at much earlier as the rate of temperature raise in the engine block is faster.
I guess the real proof will be to take a IR temperature reader, do a before and after read after identical drive.

Lexmex

I think they sell such readers at Radio Shack (not cheap here though), but it makes me think about fabricating a customized throttle body spacer to do the job. It wouldn't have to be pretty, could be a square block that does not need to be cut to fit perfectly the symmetry of the throttle body itself, but three holes for screws and you got your space. I just would have to see what material is available down here.

TunedRX300

I probably use a thick card board, use a pencil to mark the contour, and cut it out with an Exacto knife when I change spark plugs.
The main gain should be from isolating the intake manifold from the engine, phenolic spacer would work best there, paper probably would catch fire but it is probably Ok to put between the IM and TB.

Vegas300

My wife was driving the 300 last night when it started to "shake violently" as she put it and the check engine light came on. I had her go to the closest car repair shop to get the code(s). It came up with only one--P0303. Misfire on cylinder 3. Unfortunately, I knew cylinder 3 was in the rear and so I paid to have the spark plug replaced at that same mechanic shop she pulled into to save myself the time and headache. The damn mechanic calls me to tell me he has replaced all 6 plugs at the cost of $25 each plus labor...bah!

He then has the nerve to go on about how the code didn't clear after assuring me in the first place that it was a spark plug issue. I asked him to switch out a coil to number 3 and see if it comes up again. He calls back and says that the coil is actually the problem after switching it out with #4. I asked him if if he was going to order six coils and replace them all as well *sarcastically*. Anyway, I tell him to please order the part from Toyota to save myself from getting gouged by Lexus and he agrees to do so. When he calls to say the car is ready for pickup I ask how much the coil was and he tells me $280!! yikes! He then tells me I can call Lexus directly if I think he is lying....hello, no recollection of me suggesting and/or requesting Toyota? I hate damn mechanics! Right behind Car Salesmen, they have got to be the profession with the lowest morals and ethical standards.

Sure wish I would have found this thread earlier and chosen not to "save myself the time and money" with the mechanic.......yeah, $630 later I am still smarting from this one

Lexmex

I think my father paid about $125 or so for the coil at Lexus a few years back.

llcoolpass

you only needed a coil, but the coil may have worn faster due to older spark plug. i suspect this mechanic never diagnosed the resistance of the coil or anyting, just basicalyl took advantage of you.

dog eat dog world

fourup

Great site, great DIY help. At 115k miles, I thought I better change the original spark plugs and found this site when I realized it was going to be involved.

Quick comment. I found I could get to the 10mm bolt easier from underneath the car (long arms/reach). Then I realized that I could easily remove the bolt at the bottom of the support brace which is a 12mm bolt on engine block. With the bottom of the support brace free, the throttle body moved back easily without having to struggle with removing the 12mm bolt behind the throttle body, which attaches to the support brace (leave brace attached to throttle body). I could also replace both the 10mm and the 12mm (engine block bolt) easily when reinstalling, so everything was as originally designed by Lexus.

Thanks again for a great site and all the helpful info. I have to remove a door panel next...yes there's a DIY on that as well!

mrbeefy65

I just removed the throttle body when I was replacing my IACV and the spark plugs while I was in there.

I removed the three nuts and the 12 mm bolt, didn't have to remove any other bolts (I have a 2002, dunno if it is different). I happened to have a ratcheting combination wrench (craftsman) that made that 12 mm bolt a snap, the wrench fits right between the Power Steering metal line and the throttle body. I would put it back on since the throttle body is not light and leaving that bolt off would put unnecessary load on the three studs/nuts. I had enough room back there to put it back on without much trouble...