I prayed to God very passionately asking him whether or not The God Delusion was true and after I felt this tingly warm sensation telling me it was. I had done the same thing with The Book of Mormon multiple times and felt this same sensation, and I was told in church that this was the Holy Spirit telling me that it was true. I had been taught I could pray about anything and the Spirit would tell me whether or not it was true. After being told by the Spirit that The God Delusion was true, I decided that the only explanation is that what I thought of as the Spirit was just happening in my head and that it wasn't a sure way of finding knowledge.

I've always wondered about that. People talk about praying for guidance and receiving it, never quite got what they were talking about before now.

Yeah, I suppose what you describe fits with it being more that the book encouraged you to reexamine your beliefs than it's arguments persuading you as such, which makes sense.

Incidentally, I can't help wondering what would you have done if the Spirit had told you it was bunk ;)