My first question is about an idle issue. It dies right after it start's randomly, but if it is the immobilizer kicking in, would it still want to stay going then just give up? I can put my foot on the pedal and give it some gas and it'll stay with me. Some violent shaking for a few seconds, but it'll stay with me. But here's the catch, I can leave it on "On" and turn the key to start again (I heard the immobilizer doesn't allow this) and it'll start right up. And as far as this point, it will start right up second time, perfectly. My ISC motor was pretty gnarly, but I cleaned that and it went away for a little. Battery's pretty new, both of them.

I'm also want to get your guy's opinion, I'm heading on 400k kilometers soon (Seems so much worse than 250k miles even though there the same :P.)
Honestly should I just get a new(used) engine, skip the timing belt and water pump change for this one?

I would suggest that it would be something more simple like a vacuum leak, fuelling or ecu issue.

Check the voltages on your TPS, check the throttle body for cleanliness, and correct gap on the flap. And a vacuum check is a good idea. Could also be you picked up some dirty fuel, maybe pull your fuel filter and check it for blockages as well. pull the plugs and inspect those. They will tell you quick smart if there is a problem.

Check the voltages on your TPS, check the throttle body for cleanliness, and correct gap on the flap. And a vacuum check is a good idea. Could also be you picked up some dirty fuel, maybe pull your fuel filter and check it for blockages as well. pull the plugs and inspect those. They will tell you quick smart if there is a problem.

Reasonable points. Spark plugs should be checked and replaced, or at least re-gapped. Fuel filter change sounds like a good idea too.

Alright thank you, I cleaned the outside-ish of the throttle body. (Before the flap). Vacuum check definitely is on top of the list. I replaced the fuel filter not too long ago, always fill up using Shell gas. Hopefully the other points (tps, flap) are easy to find :). I'm actually oing to see about cleaning the throttle body (taking it off this time) here in a little. But my multimeter is broken, any way around that?

Sounds exactly like the issue I had when the battery was on it's way out. New battery solved it. Same issue in my sisters Verada.

Pull your air induction hose off, and the flap is right there. If the engine is on the way out, it's possible there is some oil fouling your goodies in the throttle body and fouling the gap, too. Some paper towel and clean-a-carb will sort that out. On the multi meter..... maybe replace it?

Lol yeah, I just was seeing if there was another way, for the multimeter that is. Best place to go isn't really the best place to go at the moment :P.
I know where the flap is I just didn't clean behind it, the throttle body cleaner just seems too strong for me to just spray down my intake manifold. Rather would take it off.
For the engine, it's not so much was it on it way out, but I know 400k km's is a lot.
Fairly new battery (3 mo?) could it have gone bad that quick>

If the alternator is crap, then it can kill a battery within weeks.

Ooo that makes sense. Best way to tell if an alternator is nearing its life's end? Back when I had my multimeter working, I would idle around 14.0v. I'm going to pick up a multimeter here hopefully in a sec.
But I'm tired of guesswork, I may just take it to a shop.
I'll tell them what you guy's have advised, thanks.

Except I just remembered, I went to the shop that knows the car. (Previous owners took it there all the time) and told them about the issue. But I said it was random, and out of respect they said if it doesn't do it, then they won't diagnose it. Trying to save me money in a way. I just hope it does it.