occasionally feel like it skips a beat

I have a 2004 pontiac grand am with the 3400v6. when its cold its hard to start and when I drive it down the highway it will occasionally feel like it skips a beat. When it does this the check engine light never comes on and if I lift the throttle then pull up it comes back on.

New tps, thermostat, engine temp sensor and fuel pressure regulator. Ecm not throwing codes when car