Engine Mechanical problem
1996 Mercury Sable 6 cyl Automatic

Has new spark plugs/ wires, coil pack, voltage regular, battery, EGR Sensor (DPFE), replaced a few of the vacuum lines, which all are holding a good vacuum. I'm still getting an EGR code but that's been a problem for awhile and never had a problem with starting, no other codes.

At first it happened when the weather got colder and it was sitting outside it took several tries to get it to start, it would crank but not start. I did a fuel pressure test when it wouldn't start and the reading for when the key is on, came up fine.

Last night went to start it and it would not turn over, even after several tries. I can hear the fuel pump prime. This morning it started up just fine.

Sometimes even after sitting for awhile, it starts then other times it won't .

Any suggestions. I'm getting frustrated.