Hello
I have written about this before but it continues to confuse me
I just replaced all my intake plenum seals as I suspected these were leaking air. I'm now stuck as to why I still hear a sharp hiss when I press the throttle? Also noticed an injector was leaking badly out of the top. Does this mean injector is bad or can I try replace the seals? Also any idea on what could be making the noise? DM if you'd like a video
Thanks

 

Injector not seated proper will most certainly cause an intake leak.
https://www.japan-parts.eu/lexus/us/...jection-system

 

I pickup an injector seal kit today, but after the drive home from work the issue seems to have stopped... I feel kinda dumb here but it was literally pooling on top of the engine this morning and now doesn't seem to be leaking. Am I anywhere near correct in thinking that maybe I fixed an air leak by refreshing those plenum gaskets and the ECU had changed A/F mixture therefore causing a sort of bottleneck/overpressurisation and a leak at the seal? Then relearned normal AFM and stopped leaking. I will keep the seal kit to install another day anyway, but now I'm out of ideas on what could be causing an audible hiss when I press the throttle. I've spoken to a friend who noticed his 1mz Camry also does this. Is it possible that this a normal sound/function? I noticed there is also still a slight constant hiss coming from the 'intake air control valve' next to the brake booster, which I assumed was from the old plenum gasket. Are the valves known to even go bad, or cause this noise? Please let me know if I've missed something thank you

 

Leaks normally won't fix themselves so keep a close eye on that. The hiss would most likely be a leak in the intake tract or vacuum leak. Easiest way to check for that would be with a smoke machine.