Not Ready status for OBD reading

[Heath1992]

Took my truck to get an inspection and failed the emissions and the code I got was a mass airflow sensor code. So I replaced the MAF sensor and drove it a couple of hundred miles over the course of 3 days and brought it back to get inspected and failed again but this time with the not ready status on 5 items. I was told I just need to drive more. I've since put 250 more miles and bought a scanner but the scan is telling me 5 incomplete items. My question is, are there any other factors that can cause the computer to not perform the tests and still read as not ready besides just not enough drive time?

[maxwedge]

There is a specific drive cycle procedure that should be done to restore the emissions monitors, of course if you have an existing hard failure code, this will not work. Google GM drive cycle for your vehicle. Follow the procedure.