Edit: I'm stupid. Thank you everyone for your help.











Doing due diligence on spark plugs, may end up replacing the leads as well. I am going to test the existing cables before doing so.

I found the following part; Lexus 90919-22379 Cord Set, Coil & Spark:
https://www.lexuspartsnow.com/parts/...919-22379.html

https://www.amayama.com/en/catalogs/...-spark-plug-33

The problem is, it only fits 2nd generation, pre facelift: 10/1994-07/1997. My car is a 98' with VVT-i.

The ignition page on Amayama only has the plugs and the coils:
https://www.amayama.com/en/catalogs/...-spark-plug-33

I cannot find a set of new OEM leads for my engine... set not exist for the 1UZ-FE w\ vvt-i? Is the only option ordering an aftermarket NGK or Denso set?

P.S I also think the part of this service would also be the rotor\distributor? Found here:
https://www.lexuspartsnow.com/page_p...ds=distributor

Would there be any other parts of the ignition system? Rotor --> Distributor --> Leads --> Coil --> Spark plug?

Individual coils for my car @$100\ea where you need 8 of them, where the whole set I found above is only $200... why the discrepancy?

 

1998 has 8 coils no wires.

 

So the coils just plug directly into a normal wire harness, there is no distributor\rotor\leads?

The reason I'm looking into this is the last time my spark plugs were changed is unknown. May as well just get it done.

& I'm also still having a rich condition at startup. And in neutral, the engine "stumbles" as the RPM's fall. Around 1800rpm there is a vibration as the engine is decelerating. Can a misfire happen as the engine revs are decreasing under no load? No codes\issues detected by the ECU but I'm wondering if something is on it's way out.

 

Correct no distributor.

To unravel the mystery of a bad running engine you need a code reader that displays live data. You can see engine temperature, fuel trims, any misfires (not all cause a CEL).

 

Beautiful thank you! Boy do I feel like the noob asking that question lol.

I'll take a look at the scanner this afternoon.

 

Right. Good week to get some parts from https://parts.belllexusnorthscottsda...tjfil0wprgwzff
17.76% off all parts and free shipping. Good time to stock up on anything you might need. The plugs are 90080-91180.

 

Be careful with removing the coil connectors. The connector locking tabs become brittle with age/heat. Often times they break off no matter how careful your handling. When I removed the connectors for a plug change, all eight of the connector locking tabs broke off.



OEM connector housing P/N: 90980-11150.

I don't know how Toyota supplies this P/N; pigtail or just the connector? I wouldn't bother with cutting and splicing. I'd unpin the old housing and insert the wires into a new housing. I got housings (and terminal removal tools) from the link below. Just use the Toyota number in the search window.

https://www.corsa-technic.com/index.php

 

Thanks for the link for the discount this week. <3



Checked the scanner. No codes. No misfires reported. Yet another puzzle to unpack!

(p.s it's not motor mounts)

Duly noted, thank you. I will cross this bridge when I come to it. So far, I've had no issues with my cars plastics becoming brittle. It's been garaged its whole life and things are in wonderful condition.

 

Does the 1UZ suffer from misfires due to the VVTi control valves? I don't have much experience on the 1UZ.

 

Is what I'm feeling actually a misfire? I have no issues at idle, nor under load. Car idles perfectly and under load, pulls perfectly with no interruption in power.

The only way I can replicate it is putting the car in neutral and revving the engine. As the engine is falling in RPM crossing 1800rpm, that there is a "shake" introduced into the car. It doesn't feel like the rotational inertia of the engine when you rapidly step on the throttle either. It feels like the engine "stumbles" and someone bangs on the chassis with a rubber mallet once or twice within 100ms, as the car is passing through 1800rpm on it's way back to idle.

I do not know if it happens while driving when the engine is under load. It feels like it shifts reasonably fine and I don't detect weirdness there.