1998 Dodge Stratus ENGINE IDLES rough

I put knew spark plugs and air filter. Car feels like it wants to die when stopped at red light after driving 30 miles to work. Rpm reves up. Going 50 miles an hr and it wants to cut out while driving, the car check engine lights flashing and it starts shaking. Then goes to normal. Help. Im on the freeways and highways every day for long drives.
thank you
kathy