If the vehicle is hard to start after setting overnight, the problem could be the fuel pressure regulator has failed and is allowing the fuel pressure to bleed off. A failed fuel pressure regulator will should be replaced.Google+
Car Problem Reports
Nissan Sentra Fuel Pressure Regulator May Bleed Off Pressure Overnight
Nissan Sentra Problem
Engines Affected: 1.8L 4 Cylinder, 2.5L 4 Cylinder
Average Mileage: 90,775 mi (26,000 mi - 210,000 mi)
Visitor, 2002 Nissan Sentra, 1.8L 4 Cylinder, 210,000 mi
After sitting overnight engine floods and will not crank without removing plugs and drying them, this only happens once or twice a week. Also using excessive gas.
Visitor, 2004 Nissan Sentra, 1.8L 4 Cylinder, 75,000 mi
engine hesitates to crank or takes to many turns to start the car. Once you drive the car come back and let it sit, try to start it again and it takes a few times before it does decide to start
Visitor, 2003 Nissan Sentra, 1.8L 4 Cylinder, 110,700 mi
I have to crank the car 2-4 times before the car starts.
Visitor, 2002 Nissan Sentra, 1.8L 4 Cylinder, 180,000 mi
Wont hold fuel presure
Visitor, 2005 Nissan Sentra, 1.8L 4 Cylinder
Has a veryhard time starting, specially after a couple days parked.I removed air cleaner intake,filter is new.Engine sounds like it wants to start,but takes a long time.Finally fires.
Visitor, 2005 Nissan Sentra, 1.8L 4 Cylinder, 116,000 mi
Car would have a problem starting 1st try 1/10 times when got it at 51k miles in 2007. No big deal, just prime it and it starts, right? Now it is long crank hard start every time but no problem once running.
Code po 301 random multiple misfires is the check engine light I have.
It takes several primes and cranks to finally get started.
Haven't had money to fix.
Looks like from research its the fuel pressure regulator in the fuel pump assembly. There's a TSB on this and people have continueing problems after shelling out 250 to $300+ on just a fuel pressure regulator or the whole fuel pump assembly or people going through multiple fuel pump failures.
Visitor, 2004 Nissan Sentra, 1.8L 4 Cylinder, 82,000 mi
Long cranking before start.
Visitor, 2004 Nissan Sentra, 1.8L 4 Cylinder, 130,000 mi
had the pressure tested due to the fact the engine will not start right away its over 800.00 to replace
Visitor, 2006 Nissan Sentra, 1.8L 4 Cylinder, 88,000 mi
Same as above. When letting the car sit for any length of time, it will turn over for several seconds before starting.
Hard to start in the morning, and if it's been sitting for more than an hour or so.