Maarifa

So, the short version: I got a high-pressure underbody wash, and it would appear my canister is shot now (wish I had known about the canister before!). My question is will that affect my cylinder? I have the dreaded five codes, but also the infamous P0303 for cylinder three. Rough idle, worse driving under 45mph, abhorrent acceleration. Car has made it to a very hard 158,000 miles without any major issues. She's an '06.

Thoughts?