Hi,
The idea that you hear a howling sound is likely related to a vacuum leak. Have you checked for leaks? If not, start with that. Here is a link that explains how it's done:
https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge
Next, is the P0443 the only code that was found? Also, do you have a live data scan tool? If you do, could you let me know the short-term fuel trims?
One last thought. Have you checked fuel pressure? If not, I should be able to tell from the fuel trims if there is a possible issue with pressure, but the idea you hear a hissing could cause a lean mixture as well.
Let me know as much as you can. For example, did this start all at once? Also, does it do it regardless of engine temp? Additionally, I attached info below that may be relevant to the problem described. Read through it and let me know if you have done any checking on this system
One last request. If possible, record the howling you hear from the intake and upload it for me to hear.
Let me know.
Take care,
Joe
See pic below.
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Sunday, November 7th, 2021 AT 7:29 PM