[djfox1]

In case anyone read my post, I wanted to post a followup about what finally fixed this problem...I ended up having to replace the power steering pump. I guess the power steering pump was slowly going bad, which triggered the engine code...but the pump was working enough that it never bothered to occur to me it might be bad - until one morning I discovered all my power steering fluid on my driveway. The reservoir was leaking, and of course, you can't simply replace the reservoir - you have to replace the whole pump.

A side note to any poor soul who ends up having to replace the power steering pump...the labor alone to replace it on a GT is going to run your over 400 bucks. I ended up bending over to the tune of about $700 to have the ps pump replaced. Both the dealership and my trusted mechanic quoted me about the same price, so I can only assume that this pump is one royal pain to remove and replace.

Anyway, the new pump caused the p0551 code to go away.