Third time unlucky. With the pump running, counted to 5 seconds and started the car. It stumbled. I think the most frustrating thing is that I can only test solutions once a day and need to verify the fix by testing the same thing over a number of days. 

Only way to do it sometimes. Do you want to come over and borrow my MAP. sensor for a few days?

Lumix

Admin
It sounds like you all need something like this - http://www.okaauto.com/EFI-FPP.html

Horay for the long weekend.
 
This morning tried jumping the fuel pump again. First time I did this I pulled the jumper before starting the car and the car stumbled on start up. This time I left the pump running waited 5+ seconds and started the car. It fired up fine. I will continue to do this each morning over the weekend to verify that it just wasn't one of those days where it starts fine.
 
Will keep you posted. Cheers!

I did tell you about this early in this thread about this option, I glad you have tried it. An idea for you, add a switch for the fuel pump or wire the fuel pump to come on with the ignition key in accessories position and add a turn of switch encase you want to leave accessories on: example to play the cd player etc. This can be wired direct out of the ecu in the boot. A bit out time cheapest option.

There's not much point, it didn't cure anything and ultimately there is something amiss. Stock toyota setup has worked for near on 20yrs so there's an unknown underlying issue that still needs to be found. Is good to make progress though.

You can confirm if it is fuel related by teeing in a pressure gauge to the fuel feed line and monitor fuel
Pressure.

Have you tried adding some throttle when it stumbles? If this cures it then it would point to the cold idle control system. Not sure if these run a throttle bypass valve ? If they do it could be getting sticky during first use?

My gen3 3sgte has been doing a similar thing every now and then but I haven’t investigated it. At times driving off it feels dead and adding throttle doesn’t do anything. Feels like it’s out of fuel.

Cheers

Teeing in a fuel pressure gauge is a good idea.  With a standard fuel pressure regulator and fuel pump, fuel pressure is often maintained when the engine is turned off.  If this pressure drops of over night it might be that one or more of your fuel injectors may be leaking down which can cause a stumble at startup the next morning.
 
On my own 3SGTE powered AW11 I often see a fuel pressure of 20 psi being held for a week or more before startup.

The service manual gives the length of time the pressure should hold.
 
I have a 0-60 psi mechanical fuel pressure gauge, mounted on top of the fuel filter using the fitting pictured. With the gen2 stock intake it is just visible from the top of the engine bay. Not sure about the gen3.
An extension could be fitted to make it more visible.
I believe it is a good diagnostic tool.
https://www.google.com.au/search?q=blox+bxga-00110&rlz=1C1GCEA_enAU780AU790&oq=blox+bxga-00110&aqs=chrome..69i57.57007j0j7&sourceid=chrome&ie=UTF-8
 
 

 
 

That adapter is super handy, thank you.

As mentioned earlier in this thread, I have the same symptoms with my 99 Bathurst, all be it rarely occurs with my gen 3 3sge, but when it does happen, it sounds very much like it is starving for fuel, no throttle can be applied, as it will stall out, I just leave it chugging along for about 10secs then all of a sudden it picks up to normal high idle as it does when normally first started cold.
What is explained in other people's posts, regarding the fuel pressure, totally makes sense, but what throws me, is I can start me car every time without issue, time and time again, then it will randomly play up.
A good example is the car has been sitting in my garage now for over 2 mths straight, hasn't been started, kicked it over last night, started & ran perfectly until normally operating temperature. ????
Based on that, I don't think mine is losing any fuel pressure.
Maybe something to do with the cold start injector switch or the coolant temp sensor is my guess now.
I may change both and see how it goes.

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My 3sgte was having cold start delays. Warm starts were fine. It then started hesitating and stalling under load.
Apparently my pump was gunked up which would occasionally cause pressure loss, but was hard to diagnose because it was an intermittent problem. Pressure would be fine one minute and drop the next.
 
Hate to agree with others on this (time consuming or expensive job) but I'd also say dying fuel pump.