Starting issue

[Optimaldave]

Ok, So I've had a recurrent issue since buying my truck 6 months ago...
95% of the time, when I start my truck in the morning, it starts to 1000RPM then dies within about 5 seconds like it is running out of gas/stalling. So I turn the key again, it starts, and runs fine at 1000RPM...

It does this most mornings, and some evenings, but it has never not started, and never stalled more than once per start.

truck runs great otherwise

any input would be appreciated

Cheers

 

[Sasquatch_Ryda]

Your fuel pump is bleeding back. If you turn the ignition to the run position (without cranking it) and let the fuel pump run for a second does it still do it?

 

[Optimaldave]

I will test that in the morning.
However I have changed the fuel pump as it failed a little while back, and this had no effect on the issue

Cheers

 

[Sasquatch_Ryda]

Does it stumble when it does this or just die?

 

[Optimaldave]

REVS to 1200 off the starter, levels out to 1000RPM after starter pawl disengages, then after about 1 to 2 seconds, quickly drops to 500RPM where it stumbles for a few more seconds and dies.

Second start is always pretty much perfect

 

[IMenriched]

REVS to 1200 off the starter, levels out to 1000RPM after starter pawl disengages, then after about 1 to 2 seconds, quickly drops to 500RPM where it stumbles for a few more seconds and dies.

Second start is always pretty much perfect

What else has been done??
tune up?
fuel filter? imagine that it was done with the pump...but might not hurt to do it again

does it do this on a warm start?

 

[Optimaldave]

Have changed the spark plugs, and will do the filter soon as I only did the pump 1 tank ago, so i figured i'd give it another tank before changing it.

Cheers

 

[low_five]

I read somewhere that the idle air controller opens fully at statup, waits a few seconds and then closes.

 

[Optimaldave]

any one have any thoughts on this, it still has this issue though it did get better through out summer.

Had a full tune up about 10,000KM ago now (short of the O2 sensor)

recently it has done its usual, start, run for maybe 2 seconds, die.... start, run fine (and when it dies it straight dies like electrical has been cut off, no stumbling or trying to recover)

though i have had a few days where the truck starts and stumbles going from 1000-500RPM and bouncing back and forth for 15 seconds before dying...

also noticed that when I first put load on the engine it gets to 5km/h, then stumbles once, then runs fine for the rest of the trip

Does not stall out on hot starts, this only happens on the first start of the day, or after sitting for a very long time (number of hours)