Sluggish performance & spotty Wi-Fi availability after liquid damage.

I purchased a mid-2010 MBP 13" from someone who had spilled a small amount of beer on the keyboard of the machine. When I purchased the machine the power button would not power on the machine, however by shorting the power pads I was able to get the machine up and running.

I ended up deciding to replace the keyboard and backlight. While waiting for those replacement parts to arrive, I reformatted the hard drive, installed updates, and installed some additional programs (Office 2011, iLife 2011, iWork 09, etc) by using an external keyboard. All seemed fine throughout this process.

I installed the keyboard and backlight with no problems, everything seemed good after install. The following day I went to wake the computer from sleep and I did not have a Wi-Fi signal. Upon further investigation the Mac was not recognizing the Airport hardware. I thought this might be a fluke so I decided to restart the machine. The reboot process took about 15 minutes to boot up (sluggish performance, lots of spinning wheels) and the Wi-Fi was still not back.

I shut down the machine deciding to work on it later. The next time I booted up it started snappy and the Wi-Fi was back! I thought the issued resolved itself, however the next time I woke it from sleep Wi-Fi was gone!

Has anyone ever encountered a similar situation before? The logicboard is pretty clean, there was minimal corrosion from the liquid damage. I checked the airport card and it was not affected (directly at least) by the liquid. Typing this out it almost seems like it could be a hard drive issue (will try to replace it later today).