This is a 2000 5.4L V8 RWD. It sometimes shuts "OFF" without warning while driving, but then will immediately restart without a problem. Then is may not do this again for a few days or even a week. The fuel pump and filter have already been replaced. Fuel pressure was 26(lower than allowed) before the pump and filter swap. After the pressure when up to 34 which is withing the acceptable. There are no driveability problems when the engine is running which is most of the time and no DTCs or SES lite. This was the most common fix I could think of for this symptom. Does anyone have experience with this symptom? I'm starting to think electrical like a ground stap or something since my fuel fix didn't work. I'm basically fishing at this point.

 

eallanboggs, you responded to a post about my step-daughter's RAV 4 doing this very same thing. I wish I knew what to tell you. Do our vehicles have a fuel injector relay in a fuse panel somewhere? Could there be something in the tank that is intermittenly blocking the fuel pickup line?

 

^ sorry to but i'm in decatur alabama. you're my neighbor!

 

Fuses and relays are not intermittent. Fuses blow and that's it whereas relays are highly reliable meaning they rarely fail unless they are not used properly(such as using a 20 amp relay in a 30 amp circuit). The only thing is the tank that could cause a problem such as this is the fuel pump and strainer which in my case have both been replaced. My fuel pressure went up to 34 from 26 lb after the pump, strainer and fuel filter swap. The acceptable range is 30-45 so my fuel pressure is good. That's why I'm suspecting a loose connection or high resistance problem. I'm going to try the VOLTAGE DROP method to rule that out. Once the engine is running(which it does most of the time) there are a limited number of things that can cause an intermittent problem such as this. I'm just trying to find out if anyone has had a similar problem as mine after having already replaced the pump, strainer and fuel filter.

 

Back in the day I would say it was a coil but now with COP that's out. Things that pop in mind are IAC, Cam or Crank sensor ( bet is crank sensor).
Try to see if you have any codes, they might not be serious enough to trigger a light or warning but could point in the right direction.

 

I would guess crank position sensor.

 

The CKP sensor was my best guess too so I put bought one today and will post the results.

 

eallanboggs, I posted a couple of weeks ago about my step daughter's Rav4 doing the same thing. The Toyota dealership was unable to read any error codes on a couple of different occasions. Today, my father-in-law drove the Rav4 up and down the street next to the Toyota dealership for an hour and a half until the car acted up (the engine seamingly quit, the tach fell off, fuel starvation). He did NOTHING, except pull up the emergency brake after the car coasted to a stop, and called the dealership (he was only about 300 yards away, lucky them!). He allowed the car to remain in a literal state of malfunction. He did not touch the brake, gas or gear shifter. The tech got in and hooked up a diagnostic tool and low and behold...the engine threw a code! It was a malfunctioning O2 sensor! The tech gave it gas and it lurched on him pretty good. I hope this might help your situation some. I think the car might of actually been getting flooded and quitting until the extra unspent fuel could be burned off.

 

Did the O2 sensor solve your problem. I have a hard time figuring out how an O2 sensor could cause an engine to shut "OFF". This happens very infrequently. Maybe only once a week and luckily not at speed thus far and no codes are set. The engine shuts off and the dashboard lites go out, but the engine immediately restarts. That's what leads me to believe it's electrical.

 

Part is on order, sensor will be replaced on Thursday. I'll definitely keep you posted. The Haynes book for the Rav4 says that the upstream sensor (before the cat. converter) is actually an air/fuel sensor. The book says "the air/fuel sensor provides a variable voltage output to the PCM (Powertrain Control Module) that is proportional to the air/fuel mixture ratio in the exhaust stream." Does your problem occur in wet weather? Have you had the GEM module replaced?

 

I just checked my 2000 Expedition factory manual and its says basically the same as my prior post with regatds to voltage and PCM.

 

O2 sensor was replaced and after 2 days, the original problem has yet to reoccur.

 

This sounds crazy but it happened to me. We bought a power inverter so my sone could run his x-box on the long trips and if the cig lighter plug was not pushed in all the way we had the same mysterious shut down problems. It would apparently make and break connection fast enough that it was telling the pcm there was a short. The rig would start right back up and go for a day-week-who knows how long and then do it all over again. As soon as we unplugged the converter--problem solved. we have since started using it again just making sure it is plugged all the way in.

I also had my rig shut down a couple of times when I had a bad COP--but it was accompanied by several other symptoms too.