He told me that I should have a diagnostic test ran to see if it's the brain, sensors, or any underlying electronics. What are your guy's thoughts?
If it is a sensor, and the sensor has registered a code with the ecu, you can scan the ecu yourself, and count the # of times the check engine light flashes, the first number will flash quickly, short pause, then flash the second number, long pause then either new number or the first number again if onlyy one code has been registered.
Found this video on you tube that shows what ports to connect, and shows the how to read the check engine light.
https://www.youtube.com/watch?v=qxL6WGJGtMgIf you don't get a code, it doesn't necessarily mean the sensors are working correctly, just means that they have failed enough to register a code. I had a speed sensor in the speedometer fail, truck would just shut down to idle when cruising down the freeway, took 6 months and 3 trips to the dealer before a code registered.
I would inspect all the intake tubing, harness connections, test the coil, igniter, air flow meter, fuel pump and pressure(could be clogged fuel filter failing pump).