For those of you that have narrowed your issue down to the graphics card, there is an easy way to fix it (at least temporarily). Lots of people have had success “baking” their logic boards in the oven, but it’s a risky, time consuming process to strip the board bare and toss it in the oven.
The reason baking the card in the oven works is because it allows the solder on the board to “reflow”, thus re-establishing the bad connection that was causing issues in the first place. This technique reportedly solves the issue for ~1 month before the process needs to be repeated. Trust me, it doesn’t take long to become tired of that process.
The following technique can be completed in about 15 minutes total, and doesn’t require you to disassemble the entire logic board. It can also be repeated as needed if the issues pop up again. Instructions are:
# Turn off and unplug your MacBook. Remove the screws on the bottom of your MacBook and remove the cover.
# Inside, you’ll see two fans, each with a small wire that clips onto the logic board. Gently lift the clip that connects each fan to the logic board. In total, you’ll be un-clipping two wires (one on each fan).
# Put the bottom cover back in place (don’t screw it back on yet) and turn your MacBook on. Let it run for 10 minutes (exactly). Don’t leave your MacBook unattended during this ten minute period.
# After 10 minutes, turn off the MacBook and let it cool down. Take the bottom cover off and plug the fans back in (they clip DOWN, kind of like a snap). Return the the bottom cover and screw it back in.
# Enjoy your now working MacBook. Repeat as necessary.
This method essentially “reflows” the solder without a complete disassembly or the use of an oven. Remember, don’t leave the laptop unattended after the fans are unplugged.