Pull up to a stop sign and idle seems high. After a few seconds it drifts down to normal idle.

This happened a couple of times before, and I thought it might be my imagination. It is hard to tell with no tach and the radio on, but tonight it happened the last three stop signs before I got home.

It happens that I cleaned the MAF sensor, the throttle plate, and the idle air control valve just a couple of weeks ago when I was trying to track down my Check Engine light mystery. I sprayed some WD-40 into the IAC valve after I cleaned it thinking that it would act as a lubricant. Could that have caused a problem?

Now that I think about it, I think it did it a few times before I cleaned that stuff. I thought that my big foot was touching the throttle when I pressed the brake, but I'll bet it was this.

I will check to see if air tubes came loose or cracked after I put it together, but I doubt that it would settle down after a few seconds if that were the problem. Similarly, if some unnoticed crud were still in my throttle body, it would not settle down after time.

Suggestions?

Thanks