Help with ecu code please

I am getting codes 09 08 and 01 03.... I looked this up and it says Engine Coolant Temperature Sensor? I was getting codes 03 04 and 05 05 and I replaced the Knock Sensor last night Go Me!!! My first time ever doing anything mechanical (Girly Gurl) but small hands help it took about 30 mins. to do not bad I thought.... It runs a whole lot better and seems to have more power but again this a.m. it cut off at the red light with no warning and this time no check engine light came on!!! My rpm's did fall to around 600 so every red light past that one (when I finally got it to start again) I put it in neutral and kept the rpm's around a 1000. I am going to try a couple of other suggestions today or this evening and would greatly appreciate anyones thoughts??????

600rpms is normal (600-700). It sounds more and more like your IAC needs cleaning. Also, the KS will not trip the CEL. It is one of the ghost codes that only shows up when you manually check your ECU for codes.

~THT