I got my car started this morning (about 2F). It started decently, drove down to the grocery store. The engine got up to operating temps. When I got back in the car to head home, the engine just turned over. It took 15 seconds of putting the accelerator to the floor and it finally started. Now, even if I stop the engine, let it sit for a minute, it will struggle to start when warm. I checked the EGR valve and it moves freely. No fault code. Any ideas?