Intermittant acceleration issues Gen3

[stockyvrcalais]

hmmmmm funny this exact same problem has just come up on my car tonight....wh gen3

 

[VT_Cruiser]

When i first purchased my car i thought it was ok not having anything to reference it against. After its service they changed the plugs, leads and fuel filter and O2 sensors at my request and to be honest the difference was dramatically noticable. It could have been a combination or one of these, with a tune that made such a difference, but i would start there in conjunction with your injector additive..... good luck with it mate, make sure you post the culprit when ya find it, incase i get it again in the future :O)

 

[Haget]

Hi I have poor accelatation an surging in my gen 3 vx I've change plugs,leads,coils,fuel filter , injectors had a diag done on it no faults came up I've clean throttle body stil no difference can any 1 help me or have had a similar problem as its driving me crazy

 

[st3r3otyp3]

As the OP never got back and stated the answer, just do the above mentioned options.

 

[Haget]

Sorry ways that mean

 

[s_ikari2015]

considering you've done pretty much everything else, O2 sensors would be the next option.

 

[boojak87]

As the OP never got back and stated the answer, just do the above mentioned options.

Hey all,

Sorry for the delayed response. Three years on, still no luck! Ok list is as follows:
- Plugs
- Leads
- Full exhaust - cats, headers and cat back
- Air, fuel, oil filters
- o2 sensors
- Maf
- Fuel pump and sender
- Fuel pump relay/fuse
- Injectors
- Cleaned out TB and IAC
- Plugged in to the PC to pull codes multiple times, no results.

It's definitely running lean, it can be felt on launch. Has dead spots throughout the rev range up until it hits 3500rpms. The other tell tale sign is that it doesn't hold gear when accelerating moderately, it wants to kick down 85-90% of the time. As I've had the car longer, I've become accustomed to it however seeing as I'm getting between 11-13L's per 100Kms around town not driving conservatively, that's what's leading me to think it's running lean. I'm thinking of putting it on the dyno at my next service (now) and see if that shows anything. Maybe it needs the pcm to be remapped??? Has it activated "anti abuse mode" and won't reset with a battery disconnect?

Further to the above, I'm after a reputable LSX mechanic that can do a major service and whack it on the dyno for me in the South Eastern suburbs of Melb. I'm a little light in my hip pocket so a place that's reasonably priced wouldn't go astray (I know, I don't ask for much haha).

Cheers all,
Boojakz.

 

[boojak87]

Furthermore, could a faulty TPS play havoc? I ran a scan tool over it with the ignition on the on position (engine off), slowly revving up and the voltage went up smoothly. I read somewhere though that they can only show issues when hot? I'm reading more and more about it and think that this could be my problem as the car does shift quite hard into second gear without planting my foot and a lot of my other symptoms mirror what's on some pages.

Feedback is appreciated all.

Cheers.

 

[Nut Kracker]

You could try re-setting the TPS.

1) Un plug TPS.
2) Turn ignition to "on" position (red lights on)....Turn ignition off.
3) Plug TPS back in.
4) Turn ignition to "on" position (red lights on)....Turn ignition off.
5) Start the car.

 

[ConstantVelocity]

Did you replace the MAF with new or used, and is it stock (not descreened or ported etc)? You could try unplugging the MAF to see if it runs better - it will revert to speed-density and should run ok but will be slow because it reverts to the low octane spark table.

I would log the fuel trims and O2 waveforms while driving, also the TPS to look for dead spots. A tuner with EFILive/HP Tuners can do this very easily and should be able to figure it out. Chev's Performance in melb have a good rep and probably know more than the holden dealers have forgotten lol. If you can spare the $ a tune would make a big difference. VT timing table is very soft and they pick up lots of low end torque with a tune (but need 98 ron fuel to give their best).

Actually is it possible it's been tuned in past - could have a bad mafless tune that's running lean?