2.2.1 im+ lite kills wifi signal!

this is crazy. I'm in my room, and I have a wireless router set upstairs, I get maximum signal with both my laptop and my iphone. The problem is though, when I start im+ lite and connect it using my yahoo id and such, the freakin wifi signal drops from 52 to 1 on my iphone (numeric wifi signal enabled). How can this be? I have not moved the iphone at all, and full signal is available throughout my entire room with no deadspots. I just tried that again, holding it as still as possible, and the results were the same.
Is there something wrong with my iphones wifi? or is this something that is already known as a mishap of the iphones wifi? acsually, what wifi chip does the 3g have? (2.2.1 3g, jailbroken of course, latest version of im+ lite)
Would you guys suggest an other, better, im-ing client for yahoo? (yes, I know fring, but, unfuortunately, it freezez when it wants unsubscribe my other yahoo id)