Update:
I had a moment to open the hood and take a look around. I found that the cover for the air filter had not been screwed back on, so I have tightened it on again. I'm guessing it was left off from the last time I took it in for an oil change about a month ago.
- Could this have been the source of the problem? sucking in dirty air? The car does not seem to have gotten any better after I screwed the air filter cover back on.
- How does one clean the intake, MAP and Idle control valve?