Intermittent Dying

I have a 2001 Tacoma Prerunner, 3.4L, 280K miles, that is used on a rural mail route with a right hand conversion kit. Everything was perfect until one day while turning around I put it in reverse and it idled down and died. It started back but only long enough to get out of the road before it died again and wouldn't start but after 5 minutes of resting, it did and ran perfectly for days before doing exactly the same thing. Mechanic replaced fuel filter thinking there was blockage and it ran good for days before the dying spell hit once again; however, if you released the fuel pressure it would start back and run for a few minutes before dying. He then replaced the fuel pump. It drove perfectly for one day and once again BOOM idled down and died, rest for a bit and it would start and go again for a few minutes. It's symptoms are so sporadic and intermittent that my mechanic is now stumped. It might run perfectly or barely run at all and then it may start back or may crank and crank without success.
!!! HELP, PLEASE !!!

 

Check engine light?

 

Check engine light has not come on but code reader did report P1135 - air fuel sensor heater circuit (bank 1) and P1300 - ignitor circuit fault #1.

 

When it cranks and does not start would be a perfect time to check to see if there is any spark getting to the plugs. If not, the ignitor is the first thing I would check. Unfortunately Toyota ignitors are not cheap and trying one as a test is an expensive test. How good of shape is the truck in, is she a rust bucket or ? The reason I ask is that it might be something simple as bad grounds due to rust. One simple thing to look at is the grounds for the engine control box. They are located on the upper intake manifold drivers side… you will see a number of brown wires on a ring terminal, see if they are broken or the terminal is bent or…

 

Thank you. She is in really good shape, very little to no rust deposits. I will certainly send your response to my mechanic and report an outcome.

 

Pardon my ignorance as I am still learning myself ... if the ignitor is bad wouldn't it be bad all the time? She runs like a dream until she has her dying spell, no misfire or rough idle at all.