Someone asked about this awhile ago and I can't remember when. I had that combined with a rapidly changing O2 reading ( very high to very low, sometimes enough to send the ECM back to open loop). My case turned out to be a air diverter valve malfunction. It showed in winaldl but I wasn't smart enough to know what I was seeing.
Bob

 

Do you mean IAC problem (Idle Air Control) valve?

 

No, not the IAC, I was posting about the diverter valve involved with the air pump. In my case it was staying open when it should be closed and therefore tricking the O2 sensor that it was lean and then the INT and BLM's would try and richen things up and that was what caused my problem.
Bob

 

Oh, sorry. I got rid of all that emissions crap long ago, I forgot to think of smog pump garbage!