Spitting gas back out while I'm fueling up

The check engine light flashes when the engine is misfiring severely enough to damage the catalytic converter. This requires immediate service. I see from the information contained in your question that you have already had some ignition system work performed. That work needs to be rechecked. I would also look at fuel pressure. The gas spitting back at you is probably an unrelated problem. The tank vent is likely plugged with debris from a faulty vapor canister.

BLINKING CK ENG LIGHT IS MOST LIKELY MISFIRES