Failed emmissions High HC

[Chuck Pierce]

Well gang I now have a challenge to solve.
I could use some wisdom on where to start on looking for the cause of my 
high hydrocarbon output
It measured:
193ppm with a 120ppm max at low speed (801 rpm)  REALLY BAD
103ppm with a 140ppm max at high speed (2568 rpm)  not good but passing

I found a message with a couple of things to check
1. O2 sensor  ( new 9/02)
2. Check and clean injectors
3. Replace/clean spark plugs ( new 9/02)
4. New cats. ( new 9/02)

What kinds of codes would I be looking for when I down load them?
I also read something about a temp sensor that could cause the ECU to go 
into certain modes by its failure.

Wisdom appreciated
Chuck Pierce
91 200 tq 20v Avant