Check engine light on ...ran fine..now no spark

If you smell gas it is getting gas, if not check the fuel filter. Next thing to check is to see if there is a spark. Remove the spark plug from the engine. Have someone crank the engine with the spark plug grounded, see if there is a spark. Also check for the smell of gas in the spark plug hole.

Did you check for spark? It sounds like you're not getting spark. Check for spark. If you are not getting spark then it sounds like you might have to replace the coil packs. Is it running a L4 engine? If its running a standard chevy L4 its probably the coil packs. Try to replace them check again for spark.

Sounds like you got a tank of bad gas. That would easily cause your issues. Start by draining as much as you can, put a can of Seafoam in there, add a few gallons of fresh gas, drive to the gas station and tank up, and run that tank down until your gas light comes on before adding more. You may end up needing a fuel filter or plugs again, but with minimal run time on the bad gas, you'll probably be fine.

.A}.could be the fuel filter ..B}.converter is plugging up .C} a vacuum line has come dry-rotted and or is come unattached and is sucking air .D} .idle speed is too low ..E}.The firing order is incorrect ! ....F}.clogged air cleaner ? ...G} check all fluid levels for proper fill levels . or it could be the choke sensor ids sticking or faulty ....have you tried running any fuel injection cleaner and a good grade gas this is just a minor list of points to start with after all we all get bad gas sometimes .

Change your fuel filter. **** at the bottom of your gas tank probably clogged it.

change the spark plugs too and if the problem persists, get back

Stupid answer but the fuel filter has a check valve to stop the fuel from draining from the fuel lines .If the fuel filter is bad it would do exactly as you described

The reason the check engine light is flashing instead of on steady is because it is missing bad and the car companies did this to tell you to stop the car as soon as possible to prevent damage. That is the only time the light will flash off and on instead of being on steady.
The cause is a little harder to diagnose. It could be a fouled spark plug, a bad plug wire, an injector, stopped up fuel filter. I can't remember if that car has the distributer or the coil packs but you could have a problem there. If you have never changed the spark plugs or fuel filter, it is well over a hundred thousand miles to do so now. They say to change them at one hundred thousand but 50 to 75 thousand is better and you will get better mileage. The fuel filter needs to be changed every 20 thousand miles now days because of all the cheap gas we have to put in the cars.
This is for mechanics or technicians. If no one out there believes me about the mileage on the fuel filter, then take the filter off and see what comes out the back. Looks like black water to me.

If the car has over 100,000 miles on it, you may need to replace the distributer. I don't think the bad gas caused this issue I think it may just be a coincdence. But if you already changed the plugs, wires, distributor cap, and rotor, I would definetly check the distributor.