what is the cause flashing service engine light

Engine Misfire Spark Plug Wire Loose Gas Cap Three cases can cause the flashing service engine light.

Flashing Check engine light is caused by a misfire. Its to alert you, that you need to get it checked out ASAP. there are a bunch of things that can cause a misfire on these vehicles: Distributor, distributor cap, wires, plugs, injector, cylinder head issues, etc... You would simply need to have it diagnosed by a competent repair shop.