Q: shuts off after driving

If I was diagnosing your Hummer, I would want to know if there were any diagnostic trouble codes (DTCs) stored in any of the computer modules. I would see if the Check Engine light was on and use my scan tool to find out. I would then do a thorough visual inspection under the hood. I would test the battery and check cables for clean and tight connections. Then I would drive the H2 and attempt to get it to stall on me and see if it would restart. From there, I could feel whether it seemed like a fuel-related problem or a spark-related problem.

I would then want to have a look at the operation of the camshaft position actuator and also know if your engine has enough oil pressure to allow that system to function correctly. A technician with a scan tool on a test drive can do this for you. Low oil pressure when hot could be the reason you were told to get a new engine. However, I would recommend having a trained professional, such as one from YourMechanic, inspect the vehicle’s stalling issue to determine what repairs are necessary.