Hi guys i have 1996 ls 400 recently changed its engine which is a Japanese spec 1uz engine. After 2 weeks i noticed the EGR valve was leaking so i replaced the EGR valve and after some weeks it started to misfire. When i press the gas paddle the RPM goes down and then goes up. And some times it runs great like it should but some times makes the same problem the mechanic could not track the problem and the computer showing code P0401. (Car's catalytic converters are empty) please if you have any idea whats going on then hit me up.

 

And now i start the car and the engine is hesitating and throwing lots of code😞😥😓








Need help 😞

 

And now i start the car and the engine is hesitating and throwing lots of code😞😥😓








Need help 😞

 

I judge that those multiple codes are all related to the abnormal air to fuel ratio or the off timing. I'd check the vacuum leak using a smoke machine first. It can be made easily. Actually the lady Magda is in use of a her own made smoke machine to check the leak at the link below. I worry that your EGR fixing job might cause something unwanted. Is the EGR pipe well attached to the exhaust side and the intake side? A smoke machine can tell.
https://www.clublexus.com/forums/ls-...ml#post9434048