I've been having an idle issue since I bought my GS4. The idle, regardless of RPM until 2k+, is rough. Even up above 2k there is a vibration on the floor boards and the seats, although it's faint. The idle is not low, and it can become randomly worse at any moment, without reason. Idle is worse in park than drive, but still noticable regardless of gear.

I've replaced every possible item I can think of (all OEM):

-MAF
-Plugs
-Manifold Seals
-Injector O-rings (solved check engine light for lean condition, hoping this would fix the idle, but didn't)
-PCV valve and grommet
-Air filter
-Injectors cleaned
-O2 sensor
-Cleaned TB and checked all vaccum hoses

Check engine has been gone for 3k+ miles. I get around 16.5mpg all city/traffic which is reasonable so I don't think the fuel pump or filter is to blame. My G-Tech registers a 14.5 in the 1/4 so its running fine performance wise, it's just bothering me that I have a ****tier idle than a mid 80's econobox.

I've run out of ideas. Anyone?

 

I'd say have the dealer check it with their diagnostic computer

 

I'm out of warranty and there's a 3 week appointment wait. One Lexus dealer for the most populated part of NY

 

um i don't know what it could be man... coz' 2k is really high. most people who have the idling problem, at 1k it's already smooth

 

right, 2 grand is nowhere near idle.

 

for the record that's the rpm i am at when going 60mph in 5th