I was having bizarre issues with my iP4. Besides standing in one location and watching my bars shift from 1 to 5 and back and have the phone switch repeatedly from 3G to E, I also had a few incidents where the phone would suddenly read "No Service" and wouldn't re-connect with a tower until I re-booted it. So I took it to my local Genius Bar. The guy there said that I had too many applications running in the multi-task bar, and that ate up my available memory which would then affect cell reception. He said to be sure I always manually closed any applications I wasn't using. Then he reset my iPhone and told me to set it up as a new phone. That seemed absurd. I thought Apple had figured out this whole "multi-tasking" issue and claimed that any apps sitting in the multi-task bar didn't impact memory usage. If I have to close every bloody app each time I use it, then what's the point of being able to multi-task? In that case, Apple should at least give me some way to turn off multi-tasking. So then I went to the nearby AT&T store to explain my problem. I told the guy there what the Genius has said to me. The AT&T guy asked where I lived, and when I told him he said ominously, "Ooohhh -- you're near the college. Yeah, reception always sucks there. The kids drain all the bandwidth." He then replaced my SIM card. So I went home and spent two hours re-doing all the settings on my iPhone. It hasn't kicked into "No Service" yet, but the bars are still wonky. Anyone have any thoughts on this issue? Has anyone had similar issues? Do you think the Genius or AT&T guy was right, or just blowing smoke?