idle problem GS300 2JZGE

[Batavia]

Hi all, I have just purchased a used 2000 Lexus GS300 (2JZ GE) with 120,000km on it.


Currently the car has an idle problem when it reaches normal operating temperature (88c).


In order to prevent the car from stalling, I have to turn on my A/C which maintains the engine at 450rpm (very jerky idle though). However, if I turned off the A/C the car would stall immediately.


Well, I have temporarily fixed the low idle issue by installing a zip-tie on the throttle body valve (acting as a spacer). Currently, the idle sits at 680rpm. However, I do still have low idle (around 400rpm) when placing my gear into Reverse.


Has anyone experienced this problem? Any solution? Thanks.




Below are the readings on Techstream software via OBD2 reader (after installing zip-tie on throttle body valve):


1. When engine is not running, here are the "Throttle POS" reading:

- Untouched Throttle Pedal = 15%

- WOT (floored Throttle Pedal) = 69%


2. When engine is running with A/C on, RPM measurement on each gear:

- P at 637 until 680 rpm

- R at 460 until 500 rpm

- N at 637 until 680 rpm

- D at 617 until 630 rpm


3. When engine is running with A/C off, RPM measurement on each gear:

- P at 520 rpm

- R at 1100 rpm

- N at 520 rpm

- D at 720 rpm