Answer to: Why does the wifi only work intermittently?I had this issue. Replaced the airport/bluetooth card with no success. Started to suspect that it might be an issue with the cable connections. I have ordered a new airport/bluetooth cable. But since it takes a week or two for the cable to get here I tried adding three small strips of insulating tape on top of the cable connector (to understand which connector I mean see image under step three in this guide MacBook Pro 15" Unibody Mid 2010 AirPort/Bluetooth Board Replacement). Just cutting out three pieces that fits the black top of the connector and put them on top of each other. What this does is that it puts more pressure on the connector since the fit with against the unibody shell will be more snug. It worked (well at least for a full day so far) and the airport issues are gone! I might still try with the new cable when it arrives, but for now I am a happy camper.