Have Toyota Questions? Ask a Mechanic for Answers ASAP
I would swap the injector from cylinder 1 to another cylinder.
Erase the P0301, and then see if what new P03xx logs.
The injectors may need to be off-car cleaned.
I would also perform an upper cylinder clean with Sea foam etc.
The engines are pretty reliable in most areas.
Can you listen to this noise with a length of hose to isolate it?
It may be a reflected noise from the throttle body.
How many miles on this engine?
Have you ever run an oil flush additive prior to changing the oil?
Is it nearly due for an oil change now, and would you do one to see if the noise changes?
Do you need any further help?
I hope my advice has been of assistance to you.