Hayterssss

So, i replaced pedal accelerator position sensor, throttle position sensor, and idle air control motor. I have a 1998 Lexus Gs300 in MINT condition. The ONLY thing that is not OEM is the idle air control motor, the rest are OEM Lexus/Toyota parts. I have an aftermarket intake on it (Weapon r-Dragon intake.) not throwing codes, but when reaching certain RPMs can feel a slight "stutter" if you will, like slight misfiring, but better than before. I replaced all of the spark plugs, with NGK IRIDIUM spark plugs, there was NGK DOUBLE PLATINUM in them before. TYPICALLY this happens when the car is WARM and has been driving for around 30 minutes on the highway. Every time i reset the battery before it goes into limp mode. I'm assuming intake, any ideas on why this is happening? Was giving P1120 codes before, not sure what would be wrong with it. I've seen people get away with installing SRI's and just resetting the battery and the ECU adjusts. Changed 1 coil pack, got VERY cold recently and i know coil packs can go shot with temps being -40 here. Any suggestions? Thanks reddit.




Edit: The car when resetting the battery, gives p1120 code, VSC VC lights come on check engine light follows, i have not tried resetting the battery since i changed the coil pack about 3 days ago.

TW99GS300

P1120 is specific to the APPS. Did you replace it with a new or used one?
https://us.lexusownersclub.com/forum...comment-465953
This post explains the cause. There is a video on youtube that shows how to fix it as well. Can't find the link for some reason.