2000 Mercury Sable Hard to start

After the car sits for 4-5 hours it will not start right away. Turn the key to start and it will turn over for awhile but will not start. Turn the ignition off and try again and usually it will start. If you turn the key to the on position for about 4 seconds and then turn it off two or three times this sometimes helps. Checked fuel rail pressure and it is ok.
It makes it very hard to start in the cold weather if you don't get it started on the first or second try.
Once the car starts it runs fine. Once in awhile it will start chugging like its loosing power going up a slight grade. It will stop if you give it more gas.
Any suggestions?