120,000 mile spark plug interval?

[Lost it]

So... My RX 300 has hit the 120,000 mile mark so I bought another set of plugs for it, the right ones, NGK Double iridium or whatever, and set to seeing what I needed to do to get to the rear bank.

 

Now I'm one of those who always does the hard bit first so I had a quick look on line, and in the Haynes Manual, looked at the car and decided whatever Lexus RX they used it looks nothing like mine does under the lid... So I decided at least the inlet manifold needs to come off to gain access and started along that track.

I have the "fun" of wearing a Moon boot on my left leg since I was T boned off my bike, so not quite as agile as I'd like, but the more I looked, the more I decided to remove just to gain access to the rear of the inlet manifold and throttle body.

There's a rail in the V once the top cover is off, two M6 nots one at each end then take all the vacuum pipes off, one goes to the back of the inlet manifold and I presume works an airflow flap? One goes to the air box, another one feeds to the top of the inlet throtttle bodies, then the electrical plugs and then fold kit out of the way.

Then the fun begins. After trying for about 10 minutes to get my hand down the rear of the throttle body and the top inlet manifold I decided to do it the slower but easier way. Air filter out the way, air box off for a clean out. Top scuttle panel off, wiper motor and linkage out, scuttle tray out after feeding the cables out (what does the connector that goes to the wind screen do?) strut cross brace off, undo the brake master cylinder, put to one side for cleaning and at last "t'dog could see t'rabbit" and the two M8 nuts that go through metal supports that take vertical forces from the weight of the manifolds. A few more "earth points" on M6 studs, take the Cruise control cable off the linkage and the throttle body comes off it's studs and out the way, then the top part of the inlet manifold, stuff a rag over the inlet tract holes to prevent dropping the odd lump of coal down there and Bob's your aunties husband.

Two of the plugs were quite loose, one was tighter than a ducks water seal at the stern.

The rest is, as they say a reversal of the procedure. Then change the front bank of plugs. Then clear the fault code because you tried to start it without the Airflow sensor connected...

The old ones looked worn, and I assume the rear ones at least have been in since yr 2000. Because everything was positioned "just so" and had a memory as to where it went. And everything was pretty "click" tight as well.

And it does run a bot smoother, has to be said. But it wasn't partucularly a rough sounding engine anyway. Kinda glad it's a 120,000 mile cycle though. Bit of a pain to do.