Sorry for the late update, it could very well be a clogged cat. I had a chance to take it around the block today while it was quiet and noticed a lot of blow-by. My girlfriend took it to a mechanic (behind my back >:[ ) and they said they tried timing it all day but to no avail. I looked over every inch of the bay and didn't see any vac leaks or hanging connectors. If not the cat, Perhaps the ECU has gone bad? Thanks for all of your input, guys.