We need HTownBlue to chime in about how to remove plenum. I know he's done this several times.

 

Yes have a set of torx sockets available to remove the studs. There are 3 12mm bolts ont he rear of the Throttle Body / Intake Upper Manifold that are used to brace the assembly. They are each attached / feed through a hole in a flattened pipe that in turn bolts to the engine block below.

You need to remove these 3 bolts. Use a stubby 12mm ratcheting wrench as your clearance between the manifld and the cowling of the wiper area is slim.

If you are doing the entire job, I would replace the gaskets. Also, if you have a very high milage vehicle I would also replace the valve cover gaskets while you have the entire assembly off as they will leak at about 225K or so from the rears.

I did mine in January and replaced all the gaskets and the valve cover gaskets while I had the assembly apart. I also replaced the 3 rear coils as I had 180K and in my first gen they gave out at 210 K. REPLACE AS MUCH AS YOU CAN WHILE YOU HAVE IT APART.

It is a big job but nothing too technical. Make sure you mark with white paint pen your vacuum hoses and where they go or you will likely not remember them.

As for the torx, you do need to remove all manifold bolt studs. There are 10 bolts I think...and they need to be tightened to spec and in order. Email me for this info: htownblue@gmail.com

Hope this helps guys. It was too big of a job to take photos or I woudl have like I did my bearing job.

 

Sometimes turning the headlamps switch on drains the electrical system faster after disconnecting the battery.

 

HtownBlue,,,and,,,thomas1 - If only I knew then what I know now, I wouldn't have sore ribs from leaning on the front radiator support for many hours, cut and bruised hands from reaching thru the too small gaps around the plenum to get two fingers on the middle plug; etc. But the good thing is I try to learn at least 3 new things every day, and now I only have 1 to go, thanks guys!

 

just tackled this

new thread here:

https://www.clublexus.com/forums/rx-...with-pics.html

 

I tackled this job over the weekend. I replaced all 6 plugs, the PCV and cleaned the throttle body...all without removing the plenum or any of the fuel injector rail assembly. The only parts I removed were the air filter housing and it's hose which attaches to the throttle body.

I agree this is a tough job. It took me 6 hours and I had some bruised up hands afterwards. If I had it to do over, I would purchase gaskets and remove the plenum for easier access...then replace the valve covers gaskets since as mentioned it's a lot of work to remove all these parts.

Almost forgot...I had the same high idle/check engine light problem reported by others after a spark plug change. I had failed to disconnect the battery prior to completing the work, so the ECM had not reset. Disconnecting it afterwards for approx 30 mins did the trick. High idle and check engine light issue resolved.

 

Sorry to revive an old thread, but I came here looking how to increase the idle speed on the wife's 04 RX330. 210,000 miles and the idle is just above 400. The AC compressor kicks on and off quickly I suspect because the idle speed is so low the system can't tell if it is charged properly. I will be tackling the spark plug change procedure and see if it brings up the idle speed./

 

This happens often when the throttle body is NOT clean and has carbon build up. When plugs get less efficient with spark the throttle body has to compensate with functioning at a different opening angle to get the proper air fuel ratio. When carbon builds up on the throttle body, and you then add fresh new hot spark, your air fuel ratio changes and the engine defaults to a higher idle level even though the throttle body is trying to compensate but can't due to the build up.

Clean an it and thank me later.

 

Idle speed has little to do with compressor kicking on and off. System pressure would be the culprit here. Sensors are telling the compressor it needs to kick on and off for whatever reasons. Low pressure high pressure etc etc.

 

Thank you for posting this tread.
Did you have to buy any replacement gaskets? Intake runner gasket, throttle body gaskets, etc?

I am trying to put together my parts list. So far I have Spark Plugs and PCV valve.

EDIT: Oh boy, I found some "ultra cheap" plugs on ebay... then I google, and found that there are almost exact copy Denso Fake Counterfeit plugs. Be aware. From the pictures, I would not be able to tell them apart. The main difference is that the fake does not contain iridium center posts.