Help diagnosis: Stalling Sputtering (fuel pump?)

[Babyboy11]

Gentlemen, (and ladies)'Yesterday, I was driving at about 65 miles an hour (high RPMs) and my 94 Pathfinder started sputtering, as though it was not getting any gas. I had about an 1/8th of a tank of gas left. The truck sputtered and then stalled and then would not restart. (A couple of weeks ago, the Pathfinder sputtered, hesitated and died with about 1/3 of a tank of gas left and would not restart. I went back to it about 2 hours later and the truck started right back up.) Yesterday, the starter and battery were totally turning over and had plenty of juice, so I don't think that is the problem. COULD ANYONE HELP ME NARROW DOWN THE POSSIBLE CAUSES and how I should verify? Here's what I'm thinking...1) Fuel Pump2) ECU3) Sylanoid?
Modified by Babyboy11 at 12:46 PM 9/25/2007

[02QX4ME]

Could it be vapor lock?What you described is exactly the same as what happened to my 86 Sentra. Gas has got moisture in it and turned into vapor when hot.

My 86 Sentra had a mechanical fuel pump which was found to have lose some pumping force over the years. Driving it in July in 1991, every one house or so it quit. I took a break and came back in an hour or so and drove another hour or less, and it repeated the same pattern.

Electrical pumps have high enough force so a little vapor in the gas line should not matter (only my guess).

Well, I could be wrong...

[Babyboy11]

I'll check it out today after work and see if it restarts when the engine is cool.

Does anyone know if you have to drop the gas tank on a '94 Pathfinder in order to replace the fuel pump? Thanks!

[03Chillinkoot]

maybe it just needs a tune-up??

[Babyboy11]

I actually think it might be vapor lock like the gentleman said before. It runs great, idles perfectly etc. When the vapor lock occurs, I have to wait till the car cools down and it starts back up and runs perfectly again! Weird.

If anyone else has any suggestions, please let me know.

[02QX4ME]

The first time it happened to me, AAA towed the Sentra to a nearby shop. they tested the fuel pump pressure and found it was very low, something like only half of the spec. I didn't replace the pump that time as I just graduated from college, trying to save small money (a wrong decision). AAA told me to try putting a little diesel in the gas tank. It diddn't work.

I drove all the way from FL to CA and replaced the pump. CA was never that hot. Vapor lock never happened.

By the way, under my QX4 rear seat, there is a lid with four securing screws on it, and a bundle of wires going into it. Maybe it's the fuel sensor (showing low level), not pump.

[88pathoffroad]

There are a few things that can cause that problem. Sometimes it's the power transistor for the coil, sometimes it's fuel pressure, sometimes it's bad wiring, it could also be something entirely different.

I've never ever seen a WD21 Pathfinder vapor lock. Not to say it's impossible, but it's very uncommon if it is at all possible.

There should be an access hole in your cargo area under the carpet for the fuel pump. No need to take the tank off.

[Babyboy11]

OK,I replaced the fuel pump two weeks ago and the Pathfinder was driving great. I even took the Scouts on a camping trip two hours away last weekend. Then, today on my way to work, the car starts sputtering occasionally over the course of about 2 miles. At the end of the two miles, the car just dies. It turns over and over an over and over without catching fire. Then, twenty minutes later, the car just fires right up and drives and idles perfectly. I just cannot figure out why it would start up after the passage of 20-30 minutes???? Here's what I'm thinking:

1) Fuel Filter2) Fuel Injection?3) Fuel Pump Wiring (how do I test this??)4) Coil (How do I test this?)5) Any ideas? Thanks!!

[losconchosnos]

I've had a WD21 since new in 1988 and I would be looking at something simple like changing the fuel filter first. This is a pretty rock solid vehicle and I have had very few faults in 250,000 kilometers.Chances are it's just accumulated dirt from over the years.

If it still sputters I would drain the fuel tank and flush it out and back flush the fuel line before I start looking at the fuel pump or carb.

When was the last service done?