JDS really knows what he is talking about, and gives both good advice and service.
If you can get it, CRC MAF cleaner is worth a try, but the MAF wire doesn't last forever.
MAF should have a CO% adjustment via 3mm hex key into a hole on the control box on the side of the MAF. Workshop manual shows the adjustment procedure, and Porken did a write up on how to build a simple test circuit and do the adjustment. Check Porkens site
http://www.liftbars.com/home.htm#Blinkr