Its blinking because its a missfire that could be damaging to catalytic converters.It means do not keep driving. Could be a number of things and if I start mentioning parts that MIGHT cause this problem you might go and buy these parts and install on a guess. That rarely works. I think its time to find a good professioonal and pay the justified price for their knowledge and training to do the diagnosis that you need.
Cylinder misfires can be from a variety of different issues. The most likely 2 are spark plugs (which you did) and next is faulty ignition coils. You can try the ignition coil replacement but if that doesn't fix it you will be out about $100 dollars each and still probably need service tech. assistance.