My Sentra starts rough.

Why go to the dealer?

Try this first-when the problem would happen:

Turn the key to the on postion without cranking it. Wait 5 sec. & Trun it back to the off position.

Do this procedure 4 times.

Now crank it, does it start right away?

I'm not sure of the other prospects on it.

You can try to find the problem by checking the vacuum of the fuel pressure regulator, if gas is coming up the tube instead of air, it may prove the diaphram of the regulator is cracked.

For what it matters, if you contact a local snap-on dealer
www. Snapon. Com
he can refer you to an independent garage that can work on them. The aftermarket works hard to keep up by necessity.

Another possiblity is a carbon build up that soaks the gas before it burns it, this should be done regardless of the symptom:

I would try what I call an air induction service.
I like to use castle hydroblast. You spray it into a vacuum line such as the brake booster line if nothing else is accessible. Full spray for 3 minutes, stall the engine with it or have somone kill it while your spraying. Let it set for a few hours then take for a short drive in low gear, revving the rpms to help break it up. First use Castle cleansrite to clean the throttle bore. Try to get the throttle plates scrubbed good with a brush, while your spraying. Use a rag to wipe the carbon out between brushngs. Seafoam is another good product, but smokes a lot.

IF you can't find Castle, here is my rep's email:
robw@castlepackspower. Com

Try the fuel pump relay-Why, most EFI uses the oil pressure sending unit to back the F/P relay if it goes bye-bye to keep the engine going. If its wired like this-all it takes is 4lbs to close the OPSU then the engine will fire up. Or the cold start valve not kicking in between that time.

Have the fuel pressure check to include the coolant temperature sensor.

A fuel pressure check will tell you something about the injectors, filter, pressure regulator, and pump.

The reason for the key procedure was to see if the check valve in the pump was failing and allowing a bleed back. But after reading the post again, it runs good when cold thus my thoery is invalid.

Service Writers :roll: