Did you se Lexus plugs? Also a lot of Fake Lexus plugs being sold as out there.

 

Crazy but true, I purchased my plugs at the Toyota dealer.

 

Update:

after changing gas stations, using chemical cleaners for catalytic converter and changing the PCV valve, the car is back to its original self. The lagging acceleration and the smell is completely gone.

 

What about Shell gas could be a potential issue? I use shell as its Top Tier in hopes of longevity and no cleaning should be necessary.

 

I genuinely don’t know. Someone suggested it and I am trying it out. It could just be the chemical cleaner and changing the PCV valve.

 

I also use shell 93 on my Is300 and my WRX, I’ve never had an issue with their fuel. Unlike a local Mobil that discounts their fuel, my tuned wrx detonates and pulls timing with that fuel, clearly it is not 93oct as it is labeled. Meanwhile with the local Shell 93 the WRX makes all the power without any issues whatsoever. I’m not saying every Mobil Station cheats, my local one does.

 

Here in my area, I can only use up to 91 octane at Shell. So that's what I stick with. Car is a 2016 model that was abused with 87 gas from the prev owner for 4 years. After multiple uses of cleaners, its A1 at 123,000 km. I'll change the original sparkplugs and PCV valve on my next oil change.