Apple is looking into reports that iOS 4 is causing a number of issues when installed on iPhone 3G units. The Wall Street Journal reports that a number of user reports have cropped up on Apple’s support forums, with the most common complaints being that the phone is slow after the upgrade, that it drains the battery quickly, or that it gets unreasonably hot. “This phone has gone from being a dream to constantly annoying me. Not a way to make friends. I would upgrade to an iPhone 4, but I’m feeling pretty angry that Apple has forced my hand by making my 3G unusable,” said one iPhone 3G user on Apple’s support forums. An Apple spokesperson confirmed to the WSJ that it is aware of the reports and is looking into the matter, although it is unclear whether the problems can be fixed with another iOS 4.x update, or whether Apple will have to release a downgrade utility for the iPhone 3G to return the phone to iOS 3.x.