Can you smell coolant from outside the vehicle? The gurgling sound is actually quite common i'm guessing, both of my Intrigues 99 and 02 both gurgle not loudly but it's evident. When your head gasket goes it doesnt always necessarily mean oil will get into coolant and coolant will get into the oil. My sisters went on her grand am though hers was overheating there was no evidence or suspicions of it being a head gasket and it was. I have also noticed intermittent coolant usage on my 99 for quite some time about 2-3 yrs and nothing has ever come of it. Just about once or twice every 6 months I have to add about 2 quarts. Did you have any other codes? The CEL is flashing because there is a very serious issue with your car. My guess is that is a bad misfire meaning if you do not attend to it you may end up having to replace the quite costly catalytic converter. Believe me it happens quick if you dont get it fixed. However I find the CEL usually does not flash when there is only 1 misfire its always flashed at me for a random or multiple misfire. Before winter I did the 99s plugs just cheapy plugs. By spring I had to replace them again with the stock NGKS.