what model navara do you have?
easy way would be to syphon the fuel out, or disconnect the fuel hoses and drain it.
petrol burns just fine and its fully mixed in the diesel.
the 2 stroke fixes the issue of petrol reducing the lube, in fact it increases lube well above what the diesel is.
with such small amount of petrol into a large amount of diesel its not a big issue, the oil more than makes up for it.
it could just be the differences in oils, especially when you change.
your running enough km that you should not get dpf issues. they are only euro5 so they should not get filled up quickly. it might clog if your burning a bit of oil.
the other thing is to check the issue with turbo control (vac...
the book says to pull the engine.
i'm not sure if its the version that you have to pull the gearbox/clutch off to get to the last two crank case bolts.
what makes you think the thrust washers need replacing?
i would check the glows. thats easy to do. unscrew the rail and put multi meter on. its possible its dropped a few but it sounds to good for dead glows.
failing that then clear air hose. check for air being sucked in. check fuel hoses for cracks, even splits at the ends. also the spill line...
injector cleaner may have swelled some of the rubber o rings etc.
what color smoke does it put out?
once started, if you stop and restart do you have the same problem?
doesn't sound like glow plug problem.
i suspect its sucking air into the fuel. you can try priming the filter and push a fair bit of fuel through and see how it starts.
i would start with a new fuel filter, make sure you change all the o rings. then put a bit of clear fuel line after the filter...
it was the patrol and terrano that melted pistons. they had a higher output version and different turbo and control system.
navara don't seam to be to bad.
highly recommend fitting a good intercooler.
remaps are difficult because they have a weird ecu. it requires unsoldering the chips and...
i would try to compare part numbers. good chance a company like dobsinsons would use the same part number if it fits and dobsinsons is a common brand downunder. otherwise you run a small risk that there is a slight differences between usa market and japan market. i have seen that in toyotas.