94 S-10 v-6 CODE 35

I have a friend with a 94 S-10 and it is giving off a code 35. He replaced the IAC valve last week and cleared the code. The code came back this week. He said his truck seems to be idling high all of the time, not just when it is cold.

Anyone else experience this?

He is thinking of replacing 02 sensor.

Thanks!

Jeff