OK... so as you may know Scrano and myself have been heavily trying to get to the bottom of this and I think I have the answer (well at least know the problem).
Background on investigations: Mine started happening a few months ago. I rarely use the car and when it started occuring was thinking it was just because it had been sitting for a while... but gradually it just started to appear more severe, or maybe I started noticing it more. I have been using BP98 for a while now so the problem was when using BP98. Tried several different servo's (all BP)... no difference.
Pulled out all injectors and had them tested as I thought they may have been dribbling when sitting for 10hours plus. Injectors tested fine (infact I was told they were the best closest performing injector set that they had ever tested).
Thought it may have been the tune, so had the car retuned by a very reputable tuner (a different tune from the first). I know for a fact that the re-tune was done from scratch as the original tune was remote (no comments please), and I had to flash a base unlocked tune back in it so the new tuner could carry out the dyno tune. Anyway... after the re-tune, problem still existed.
At this point I purchased a fuel pressure test gauge which screws to the threaded schrader valve. Left cars for days, turned on ignition (let it prime) and pressure was up at 55psi (normal). Started car, pressure remained at 55psi, and did the same thing (stuttering for a few seconds). This eliminated fuel pressure leak back (fuel pressure regulator failure).
I then rang and chatted to the new tuner. He said that he has experienced the same problem with his VF and he uses BP. He had also heard of the same problem, sometimes that it had been rectified by changing fuel brand. His immediate thought were that for some reason, after the car sits for 10 hours plus, when you start the car, it actually starts on the E85 fuel mapping (E85 compatible cars have dual maps, and switching between the maps is automated and triggered by the eflex sensor). After a couple of seconds, the Eflex sensor recognises that the fuel is not E85 and triggers the mapping change and bang your revs ramp up into a normal type cold start.
So I was heading away for the weekend down south and decided to test the theory. Ran car to "very low" and filled with E85. Drove south, and during the first couple of days of being away let the car site for 12 hours plus and then started... starts perfectly problem gone. So while I was away I got the E85 very low again and filled with United 98 premium. Drove home... let car sit for days... start car... perfect!
I believe the tuner was spot on with what is happening. Everyone who seems to be having the same problem has an E85 compatible car. Earlier VE's werent compatible with E85 and didnt have the same dual mapping so arent experiencing the problem. It appears that something within particular 98 blend fuels (differs with brand of fuel) isnt immediately triggering the eflex sensor to change back to the standard mapping. I have no idea why it differs between 98 fuel brands and why the car switches from the previously started fuel mapping and reverts to E85 mapping... but I think thats whats happening.
So I suppose to all the guru tuners out there... why would this be happening? Could it be a holden software problem? Can the setting be changed for the car to always default start in 98 map? It is happening with both tuned cars and standard cars so to me its a holden problem possibly with the sensitivity of the eflex sensor? I like to know where the eflex sensor is?
Dont listen to the crap holden is spinning for the problem. You will keep pouring money into changing out parts and it wont fix anything.