I've had my S4 for a little over a year, and the 'check engine' light has never gone out. I have examined the engine airways for cracks and leaks -- none found. Checked the air intake meter, and it's OK. Have changed the O2 sensor. Still, it burns brightly. Unless there is something else to check, I figure there is just an evil ghost in the machine. So, what's the worst that can happen if I just take the bulb out and, accordingly, have no more "check engine" warning at all?