Believe me, I understand. Based on the code, I would believe there is a vacuum leak somewhere on or around the intake. It could cause a noise that you described. Also, check the exhaust for leaks. On this type of car I'm concerned that a change in backpressure may even set the code.
Also, the Manifold Differential Pressure switch (MDP) sits on top of your intake manifold and monitors the air pressure. Check it to see if it's mounted good and maybe unplug it and plug it back in to see if there may be corrosion on the plug. Also, have someone check closely for leaks there, remove the MDP and clean it if carboned up and properly replace it. The more I think of it, the more I think that is where the problem is. You may also want to have the EGR checked for leaks, if it's stuck, or carboned up too.
Let me know what you find, or if you have other questions.
Monday, August 3rd, 2020 AT 2:49 PM