^ I was also thinking that it may be the alternator. I have it on a charger right now. How do I test to see if the alternator is giving enough charge?
It could be any of alternator, battery or fuel or even a bad sensor.
Check the voltage on your battery with the engine off. It should be 12.5V or better. If you don't know how to use a voltmeter, try this little
Equus Voltmeter that plugs into the cigarette lighter. If find it very convenient in my GTS which constantly demands battery charging.
Check the voltage on your dash with the engine running. It should be near 14V. If it is 13.5 or lower it's most likely the alternator/belt. Check out the belt to see if it's worn.
Fuel, well no easy way to tell other than if the problem persists at the next fill and battery/alternator were ruled out.
Sensors will eventually throw a code but sometimes they are intermittent and their failures are not long enough during the OBDII error measurement cycle.
Let us know what you find.