Hyundai Repair: 2000 hyundai accent- check engine light on, air flow sensor, vacuum leaks

Question
For the past 2 months I have had the problem of the check engine light being on. The car when started after sitting for the night or extended period of time will idle slowly and run rough. After the car runs for a few minutes its ok. Trying to figure out how to fix this is the problem. I have gone to Auto Zone for a diagnostic and the error code P1128 shows up. Since then I have replaced the PCV valve and both the Upper and Lower O2 sensors. I have also check for vacuum leaks with starter fluid on the vacuum hoses at their connection with no sign of bubbling or having any changes to the eingine while it is running. When I have reset the computer and driven the car for a little while the check engine light comes back on. I would really like to fix this problem, if you have any ideas that I could try that would be great.

Thanks

Answer
You've already completed most of the preliminary steps.  The two most frequent causes of P1128 are a vacuum leak in the PCV hose and a defective air flow sensor.  Just to be sure, I'd recommend making a good check of the PCV hose for holes, and if okay, replace the air flow sensor.