Poor wifi reception after screen replacement

Recently I replaced a screen in my verizon iphone 4. Everything is working properly except for the wifi reception. I have looked all over online for solutions and done all that I believe would help. I have cleaned the contacts for the wifi with alcohol. I also cleaned the whole stretch of inner frame that the wifi runs from top to the bottom, the mid frame, the connectors to the antenna on the speaker, the contact for the back plate, and the back plate. Any ideas what could be causing such poor signal? I'm completely at a loss of ideas here.