iPhone problems with reception/phone?

[simply stunning]

So I have a white iPhone 4 that I bought a few months ago, and I have had some problems with it that seam to be getting worse. When I get calls and pick them up sometime the caller can't hear me for maybe 30 seconds, or I have to hang up and call them back. I can hear them fine, but they can't hear me. Or they say I sound distant.

I will be preordering the 4S tomorrow, and the 4 I have will be going to my wife, but last night she said she doesn't want it unless I get it fixed which I was planning on doing.

So my question is this. I will be making a genius appointment, for sometime this weekend, but I can't reproduce the problem even though it happens often, when I ask someone to call me, and or I call someone trying to get it to happen it won't work. So will I have to prove the problem, because if so, I might be waisting my time. Or has anyone had this problem, and how did you handle it? I know that they will have the final say, I'm just looking for some tips.

BTW, my phone is on the latest update, and is without a case, but it doesn't help if I put a case on it, so it isn't that.

 

[FreakinEurekan]

One fairly common problem is dirt or "gunk" in the dock connector, apparently causing resistance to make the phone think it's in a dock and shutting off the mic. Or perhaps dirty headphone socket causing it to think mic is plugged in there.

I used a wooden toothpick to carefully wipe the connector in the bottom of my iPhone 4 and took care of a similar problem I was having.