So the other day in driving my 05 rx330 and I noticed intermittent power. A hesitation when stepping on the throttle, specially if you’re going uphill, it would give you enough power to get up the hill, but just barely? Shortly after check engine light came on and was blinking so I automatically thought of I must have a misfire. got home got my scan tool and sure enough. I was right misfire on cylinder three and six. So I go get the spark plugs thinking it’s gonna be an easy fix. Come to find out this project. Looks like a nightmare. I change the front three out no problem. Check the ignition coils to make sure those were OK but get to the rear ones I am attempting to do this tomorrow morning. They’re saying it’s a 2 to 3 hour job, I’m really looking for some advice on this. I do all my car work myself. I would say I’m pretty decent self taught. but I can change my own oil, coolant, flush tranny flush replace the wheel hub and knuckle assembly on both front tires replaced rear struts, brakes rotors, etc.

The black piece it’s connected to the throttlebody. How would I search that for a gasket replacement because I’m pretty sure I would have to put a new gasket on there once and get that out?

but it looks like I gotta take half the motor apart and correct me if I’m wrong but do I have to replace that gasket as well when doing this since I’m taking that off any input on this would be greatly appreciated thank you. Do I have to remove this black cover that goes up to the windshield with the windshield wipers? I seen online that someone removed all that to get to Three spark plugs. Crazy.

 

It's been discussed in this site very often. Whoever told you it's a 3 hours job it's very wrong, with the right tools you're looking at at least 6 hours... Yes it requires removal of windshield wiper assemblies, parts of the firewall, intake manifold. Buckle up you're in for a wild ride

 

. I’ve been doing so much research and I see them working on the same motor but it’s on a ES 330 and they were able to get like a swivel ratchet and get it down in there to loosen those ignition coils. But I don’t think that’s the case with the RX because you know how with the SUVs it’s more tight and pushed back. I believe I have all the tools but I had no idea what I was in store for, but it has to be done tomorrow morning six thank you.

 

Take your time.... removing the cowl definitely helps with access. Have the gaskets on hand (throttle body and air intake) and consider replacing the rear ignition coils (only OEM or genuine Denso) while you are there. If this is the first time accessing the rear bank, also look to replace that valve cover gasket and PCV valve. Take pictures along the way so you remember the hose arrangement and all the various screws that you need to remove. Replace with NGK or Denso plugs since you do not want to do this again for another 100K.
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I used to pay someone to do all my work until I realized it's the most fulfilling thing I do. I have an 08 rx400h and a 97 LS400 with 312k that runs better than the rx and my better half's 03 es300. And it's easier to work on. I just finished rebuilding the engine of the rx without removing the block due to a blown head gasket. That has taught me a lot about space and appropriate tools, especially when the engine bay also has a high voltage inverter. The keys for the rear plugs and coils for me were 1. Determining I could remove the right 12 mm stud holding the blower in place (used the 2 bolt method) because then I could lift the blower out without removing the wiper cowl, and 2. Finding out there are 2 12mm bolts that i didnt know about that have to be removed - 1 attached to the rear right (looking towards the back of the vehicle) of the throttle body and passing through the black stabilizer bar attached to the block, and the other attached to the middle stabilizer bar on the back of the blower.

Tool for the best access - after days of trying to attack those from the front of the vehicle, I used my aluminum speed jack to raise the driver side at the jack point behind the front drivers tire (then inserted jack stand). I easily slid under from the front bumper, looked up and could access the bolts with a short 12 mm wrench. Blower came right out. Having proper extensions and a good torque wrench took care of the plugs easily when again working from the top side. Don't forget anti-seize on the plugs and all denso or ngk for parts.

 

I have done this twice, removal of wiper cowl is necessary. First time for Spark plugs (220k) and second time for rear valve cover gasket oil leak. Trust me If you are in there change plugs and coil packs and do a visual on valve cover gasket to see if it is leaking. My car was 13 years old at the time, the gasket had lost its pliable and hardened, perfect for leaking. Removal of intake manifold is required. Scary first time second time not so much. Makes everything so much more accessible. there is one bolt on rear of manifold between fire wall and manifold that is difficult.

 

I agree with you. It's a big job, and since you're there, do it right! It's worth it! I had this done when I had my timing belt done (@90k) I had a small town mechanic that was a fair, knowledgble has a great reputation kinda guy.. I had all the plugs, coils, gaskets, and the air/fuel sensor replaced since they all kinda need it at 100k... That was 8 years and 46k miles ago.. I kinda figured it was THE major things that need maintenance.. that's been it.. everything runs great.. I also bought the parts so I could make sure they were Denso... Especially the fuel/air sensor.. a lot of out of market crap out there!

I am glad I had it all done at once.. no they didn't talk me into it.. I knew a tune up would be due.. and you don't want to mess with a timing belt giving out... I requested the work be done before I had a problem..

These engines are great (I wish I didn't have a timing belt) and really once every 90 to 100k miles... That engine will love you! Heck my car is now 20 years old.. AC, all the sensors, traction, everything works! And I've never gotten a code.. use OEM fluids, use denso parts.. use synthetic oil.. I also use top tier full.. just 87 octane but top tier because it cleans better so you don't get catalytic converter problems..

Change you tranny and differential fluids.. as scheduled

That car will last 500k!

 

On the RX330 you can pull the 1st and 3rd plug & coil on the rear bank at the firewall without pulling the plenum.

It's delicate work and you will need the right plug puller and sockets.

I've done it as an experiment.
​​​​​​i haven't figured out how to pull the middle plug without pulling the manifold tho.

PS, after someone does the rear bank for the first time, it gets faster and easier the next times, one hour tops in & out. This is on the RX330 but I don't know about the RX350 because it has a different engine.