Vz Commodore Auto “Stalling” / Struggling to start

[PAUL3T]

Hey guys, I have a problem with my VZ V6 Auto “stalling” and not starting sometimes. Any ideas?

So far I have:
Serviced and changed all fluids
New air filter
New fuel filter
Cleaned MAF
Checked for vacuum leaks
Replaced all spark plugs
Checked all coils
Replaced fuel pump relay
Replaced Oxy sensors
Replaces Crank angle Sensor
Removed cats to see if they were the problem
Ran 2 lots of Injector Cleaner through two tanks of premium

 

[PAUL3T]

Update: Still having this problem... have now replaced all coil packs, checked fuel lines, replaced fuel pump, replaced both cats, replaced MAF sensor, new catback exhaust.

Next place to look is ecu I suppose. Car is more reliable when bridging the fuel pump relay but still struggles at start without me pushing on the accelerator.

 

[krusing]

Does it produce any codes ?
Have you check the running conditions on the a scanner to see if its running within spec,?
that can usually give you an indication where to look.

 

[PAUL3T]

That’s the problem. Won’t throw any helpful codes. Have scanned it multiple times. Have seen codes P0627, P0629 and P0628. These refer to fuel pump highs and lows. Also was a code for running rich at idle.

 

[krusing]

Ahh, How many K's has it done ?
You say the fuel pump has been changed, was it a new one, or S/Hand one ?
Have you had the fuel pressure checked ?
Also, is this the original Motor ?
Was the car a LPG Car ?
I had a issue the other day, where I left a vacuum plug off on the plastic intake throttle body manifold,
and it produced a oxygen sensor code was lean, where it had nothing to do with the oxygen sensor,
which threw me, but remembered what I did do, and then checked and found what I HADNT done when putting back together.
This is where is can be very confusing sometimes.

 

[PAUL3T]

Brand new fuel pump, engines done 160xxxkm. Haven’t checked fuel pressure yet. Original motor and never been on gas. Have checked for vacuum leaks several times... this is why I am starting to think it’s a ecu problem