90 Lexus LS400
 

My kid recently bought an LS400. It has a stalling issue, doesn’t matter if the engine is cold or warm. I initially found a couple vacuum leaks and repaired those, did a tune up on the engine, and replaced the throttle position sensor. The fuel pump has been replaced as well. It has an aftermarket air cleaner system and it seems to be sucking too much air, I’m considering switching it back to a factory system. But I’m thinking it could use new injectors, or there may be a throttle body issue. Anybody have anything similar, and could point me in the right direction here? Any help is greatly appreciated!