E-mailing Tokyo won't do anything but waste some bandwidth, not that there isn't a lot of that happening anyway. :)

Problems like this can ONLY be diagnosed while they are occuring, anything else is a guess. When you say the pump and the fuel filter have been checked and they are OK, you are in fact likely talking about them being checked when the problem is not occuring. Now the fuel filter, I'll give you that one, if it was truly "checked", it cannot act up intermittently so it is not the cause of this trouble. The fuel pump however, and the wiring to it can in deed act up randomly at the beginning of the trouble.

The main thing is, she needs to establish a pattern to the failure if possible. Maybe it's a trip of a certain length. Maybe it's dependent on climate conditions. Lastly, she may need to help the shop/tech find the problem by driving it for the shop in order to attempt to make the trouble occur. Often times we will use a "flight recorder" to store a snapshot of data during a trouble event. That wont be a diagnosis on it's own, but at least it could give us a more narrow feild of view.

One time, I had a problem like this with and outboard motor. It took me a week to solve it. The culprit was the oil used for the gas-oil mix. A well known brand went overboard with the wax in the oil. (I read about the recall after my vacation was over.) When the oil was mixed with the gasoline, the wax began to come out of solution forming worm-like detris which proceded to suck up against the intake screen. The fuel starved engine would bog down and quit. When it quit, the suction on the pickup tube was relieved and some of the gunk dropped off allowing the engine to start again only to quit soon after.

Now think what could happen if you had a plastic baggie in your fuel tank, or some other debris. The likelyhood of this is very small, but I mention it because it is possible. The sock over the fuel inlet may be partly fouled and if there is other filmy gunk in the tank, it can get completely shut off when this gunk gets sucked against the sock. And some of that gunk can fall off after the suction is removed.

However, I hope this is not the case. It seems like an intermittnet electrical problem. The tachometer sensor is suspect. The fuel pump may be intermittent. How is a loose gas cap sensed on this vehicle? There may be a problem in this circuit.

Thank you for the suggestions. I have given them to my friend
and she will discuss them with the mechanic. These intermittent problems are such a pain!

Abbey

Many years ago, a friend had a new Toyota Landcruiser that did the exact same thing. Three trips to the dealer with the same "it must be water in the gas" answer was too much for him, not to mention the bills because it wasnÂt a "warranty" issue, so we pulled out the gas tank. No easy feat because it resided under the passengerÂs seat. We waited until the tank was near empty, then the seat had to come out, next, a sheet-metal shield, and finally the gas tank, but it paid off. Along with the few gallons of residual gas that we poured out, came a small cardstock manufacturing tag, all in Japanese characters. We put it all back together and it never had the problem again.

I know he tried to get the dealer to refund the "inspection" charges and even got Toyota Regional involved, but believe he had to go to Small Claims Court to get any satisfaction.

Gosh, am I glad I checked this forum. My Toyota RAV4 has been having the same problems!!!! Loss of power when driving, and I've been to the mechanic 5 times and no one can find anything wrong with it!

At least now I have something more to investigate!

Sooz

With any driveability problem, symptoms can sound to be the same, but in fact have completely different causes. What are the specifics of your cars problem?

Is the symptom influenced by weather?

Does how long the vehicle has been driven appear to be a factor?

Details are so important to get the car to act up, and then perform the diagnostics while it is occuring. Otherwise you risk replacing parts that are not bad and wasting lots of money.

It's too bad this vehicle can not be wheeled into John_g's shop. This is the kind of mystery he excells in.

Does the problem happen only when the engine is warmed up and the underhood temperature become toasty. maybe like a slow down after a good run at speed? If so suspect a sensor that is failing when hot, but recovers after it has cooled a few degrees. Hall effect type sensors have been known to do this. Look at controls/sensors that affect ignition. A cam shaft or crank shaft sensor may be at fault. What trouble codes have been set after a failure.

Check out the ignition switch. It may cutting off the ignition and maybe no codes will be set. The ignition switch may be opening the ignition circuit due to worn parts or maladjustment. The switch gets exercised when restarting the engine.

Good day, Abbey.
I am no mechanic, but have worked on my own cars for many years.
1) Some cars have vent valve fitted in fuel cap. Loosen fuel tank cap and drive it for a while to see if the problem goes away. Sonetimes the small vent valve in the fuel cap is blocked from dust. If that is the problem, replace the cap.
2)Most Toyotas have a vent valve on a pipe coming from the fuel tank ending at the fire wall in the engine coompartment - it allows air to go in or out as the fuel expand in the day / is used up while driving. It normally is a plastic holder about a third of your fist. Check if it is still allowing air through. There should be some one way valves in it.
3) Check the wires underneath the car going to the fuel pump for any damage. While the car is idling, move the wires to see if there is any loose contact.

May God bless you this year.
Marius

Hi, I have the same problem, you can be driving along, then all of a sudden the engine losses power but the engine is actually still running but the accellerator is all spongy, all I do is turn it off and then on and it's back to normal and it happens at random, sometimes not for weeks, then maybe twice in a week, any help greatly appreciated as I had it in the toyota garage and they don't know, they just keep changing parts but don't cure it.
Roy.

I too have experienced this problem.My garage changed the injectors and sensors,and told me to put a fuel treatment in the tank every two or three weeks or so.This cured the problem for 5 months.A week ago the symptoms returned with a vengeance.I bought a code reader and found that it read 'fuel pump line A open'.My garage have just replaced the valves on the fuel pump,and cleaned a lot of gunge from the pump itself advising me not to put in any more.they were told by the motor factors ,that this would appear to be a common fault with the rav 4 ,as they had sold 7 repair kits this month.At �272.47 a time plus fitting and vat i can only hope that is an end to the problem,time will tell.The loss of power is due to the engine management system electing to go into 'limp home mode' in order to protect the engine.I have seen several cases of this fault occuring on the web,and quite a few drivers have been told by toyota garages that it was the turbo that needed replacing at 2 grand a time only to find that the fault still occured.I hope this can be of help to anyone with a similar problem.In my case somedays it would only accelerate in first gear,and then not go over 50 mph,and it was impossible to overtake anything.