What is wrong when your engine light blink off and on and your car start choking

R u sure it's choking or more like loosing fuel to the plugs.

It is misfiring bad enough to cause catalyst damage and likely , engine damage. Do not drive with light flashing!

A flashing CEL indicates a misfire that is causing the crankshaft to decelerate greater the 10% of its normal rotation speed. This is a very bad thing that will cause the injectors to dump fuel into the cylinders at a rate that keeps it from being completely burnt off during the combustion process. This excess fuel leaks out of the cylinder head into the exhaust manifold where it collects in the catalytic converter. This is, at the least, going to kill the catalytic converter. As it burns off the excess fuel, it heats to a point that the catalyst is destroyed. If it heats up enough, it could also ignite a fire.