After successfully passing the Influence test in the first part, the middle Pass section has the option of becoming Delayed unless 2 Clues are spent. Then, the last sentence states that if you spend the Clues, you can close the Gate. If I choose to become Delayed because I don't have 2 Clues, can I still close the Gate? Otherwise, if the Investigator doesn't have 2 Clues, this Pass is really a Fail without a lasting consequence.

Seems like you are discussing card #21. For context, the text for the Pass reads in full (emphasis added to relevant part:

Believing that you can help him, a guest attempts to bribe you. Gains 1 Artifact. Seeing this, the Queen demands that you unmask. She questions you relentlessly in an attempt to discover what you've learned. Become Delayed unless you spend 2 Clues. If you spend the Clues, you gain her favor; close this Gate.

Now on to your questions.

If I choose to become Delayed because I don't have 2 Clues, can I still close the Gate?

No - the last sentence quite clear: you must have spent the clues in order to close the gate.

Otherwise, if the Investigator doesn't have 2 Clues, this Pass is really a Fail without a lasting consequence.

You are overlooking the fact that you no matter what, you gain an artifact from the bribe.

Yes, true. Gaining the Artifact is an accomplishment. I just never found Artifacts particularly useful since they get stolen or lost within 2-3 rounds from thieves on failed Encounter Cards or Mythos Cards that discard items. From the 10 or so games I have played of EH, I had Artifacts maybe 4 times & lost all but 1 without using them. Regarding the clarification of the card, to me it's a fail if you don't close the Gate, which is more important game-wise (Doom Track, Monster Surge) that gaining 1 item.

"Pass" in OW encounters implies that your exploration of the OW was successfull and that you gained insight from it; closing the gate is not always automatic, sometimes you have to pass an additional check, some others you need to spend resources (clues or focus and so on).

In the same way, the "Fail" condition implies your journey proved fruitless; sometimes you're still given a chance to close even if you fail the initial test, but this comes at a price (more difficult test, gaining a detrimental condition, and so on).

It's very important to understand that EH is no AH, and OWs work in quite a different way. I know this can be frustrating, at times.

I am currently solo playing with 3 Investigators a lot to learn the mechanics down pat. I want to be able to teach others, especially players who don't play heavier games like EH, to play in the future. Therefore, when somewhat vague situations like this arise, I need to be clear about how to resolve an issue or answer questions. Thank you both.

Sorry to hear that your experience with artifacts hasn't been the happiest. While some of the artifacts can be hit or miss depending on who draws them, there are some (for instance the Grotesque Statue which gives 5 clues) which are always appreciated.