Toyota Repair: Engine cuts out randomly, toyota dealerships, dash light

Question
I have a very odd problem with my 2000 Toyota Tacoma 4cl automatic 4X4.  It tends to cut out.  Unfortunately, I can find no pattern.  It cuts out idling, driving down the interstate, at bumps, not at bumps, with the lights on, without the lights on, in winter, in summer, you get the picture.  It has done this at least 30 times randomly dispersed between when I got the truck at 17k and now at 80k.  Both fortunately and unfortunately, it always restarts after it sits a while.  The unfortunate part is that “while” may be 10 min. or 10 hours.  I have also had problems with the truck not restarting for an extended period after the engine has been deliberately stopped.  As you might imagine, I’ve been stranded a time or two.  Naturally I can never, and likely will never, get this wagon to a shop at a time when it is acting up, so there is always “nothing wrong” by the time I get it to help.  Accordingly, I’ve had this thing at three Toyota dealerships in three states on at least 10 occasions total, and they can’t seem to find the problem.  There are also no codes at all to provide a hint.  To their credit, the Toyota folks have changed the throttle body, fuel filter, and the main computer looking for the problem and have only charged me for the fuel filter.  

Here are some additional helpful hints.  At times when the vehicle will not start, the engine will turn over but will not fire.  All the exterior and interior lights work except for two during a stall.  The check-engine light and an additional (alternator I seem to recall) dash light do not come on during a no-start episode.  When I turn the key and the check engine light finally decides to come on, I know the engine will now start, and that it does.  There is no hesitation or warning signals when the engine cuts out, and there is no sputter or other chattering attempts at firing when I try to restart.  It just runs like a top at that point.  

I replaced the EFI relay with the tail light relay once or twice during cut-outs to see if the EFI relay was over heating and sticking.  That didn’t do the trick.  Next route, I’m thinking fuel pump relay.  I need to check for fire during a stall, but I never have another person with me to turn the ignition while I check the wires.  I’m thinking about changing the wires/cap anyway, but since it does not always appear to be so clearly heat related, I’m not sure that is the answer either.  Basically, I’m stumped?  How many things could do something so sinister to an otherwise fine truck?  Any recommendations as to how I should proceed?

Thanks


Answer
Well if you have no check engine light during no start, you have no power to the ecu and it wont start and it wont store a code.

As this seems to be a wiring issue, rather than track it down, why not run a new wire from the EFI main relay to the ECU?
Who cares where the open is. Add the new wire. Dont cut the old one, just tap in.

Wiring diagram available at www.techinfo.toyota.com.


Mike