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Hello. Do you notice any clattering noise? Have you done a fuel pressure test?
Ok. That sounds very consistent with a vacuum leak. Have you thoroughly inspected all vacuum hoses?
Do you have a scan tool that is capable of reading fuel trims? If so, what are your fuel trims? that will tell us if there is a vacuum leak or not.
If you had smoke escaping, then you were unable to build pressure to do an effective smoke test.
Next, There is an o ring that commonly goes bad on the mass air flow meter. replace that ring and see if it solves this problem. It's a very common cause of random multiple misfires on your model. Let me know what you find. If you need a diagram showing it's location, let me know.
What are the fuel trims if you hold the throttle at 3000 rpm? Have you replaced that o ring?
The long term trims are indicating a very lean condition. Check fuel pressure. check to see what the trims look like with elevated rpm