I have a 2008 Buick Lucerne. The car will start and run for a few seconds then shut off. The message center says to service throttle, reduced engine power. I’ve replaced the throttle body and mass air flow sensor. I don’t know what to do from this point. I can disconnect the battery and start it but it does the same thing. Oh and I have done the procedure to program the key

What does the theft light do?

I think in 2008 it is fly by wire. Perhaps the accelerator pedal position sensor is bad.