Intermittant acceleration issues Gen3

[boojak87]

Good evening to you all,

I'm having an acceleration issue with a VT SS Gen 3. It has recently clocked up 100,000kms and went into Holden for a major service (the 160,000kms one, air, oil, fuel filters, platinum plugs etc). I explained that I was experiencing average acceleration when planting the foot and they said that after a test drive they could not fault it!

Now i'm turning to the help of the good folk at Justcommodores for assistance! Ok, so this is what happens:
1) Slight rough idle and on a couple of occasions the revs have dropped to around 500rpm-750rpm before picking up again.
2) Once warm, cruising at say 70kms/hr and planting your foot, it used to remain in the same gear and accelerate like a V8 should, although now it always wants to kick down a gear and even then, the power is just not the same (huge flat spot).
3) When climbing a hill, the car feels like it has less guts than my old VS 6 cylinder.
4) Fuel usage has been steadily increasing.

Holden's solution for something they couldn't find (HAHA shock horror!!! They always find the problems that aren't there and miss the obvious ones), was for the fuel system to be cleaned out with one of their $155 fuel cleans but before I decide to go ahead with that I thought I'd get some advice on here. I was thinking that as it is highly unlikely the spark plug leads have been changed since new, could it be possible that an arching/dead lead could be the culprit because it does feel like it's running on not all 8 cylinders?

Feedback would be heaps appreciated.

Cheers guys,
Boojakz.

 

[jay_wr8]

before you pay to have the fuel system cleaned out get a bottle of injector cleaner and run that through to see if that helps

 

[tigass]

I had very similar problems with my gen iii. It could be a combination of things. The leads (according to my mechanic) should be replaced at 100k. Also check things like fuel filter caused by dirty fuel. Simply putting in a fuel additive won't always fix the problem asap. Also try running the car with the best possible fuel, ie premium
with 98 octane. I would not recommend at this stage going for holdens additive as often as the case their product is just a glorified fuel additive you can buy at supercheap etc.

 

[rb26dett]

o2 sensors or fuel pump, or combination of both.

I would start with the o2 sensors first.

 

[hwy747]

I was having similar issues with mine. Turned out I had 2 clogged injectors. Got them cleaned out and it is noticably different!

 

[boojak87]

I've running nothing but premium in the car since I've had it. The problem first showed it's head after I topped up with Shell vpower. I've run nothing but bp ultimate ever since hoping the problem would go away but it's been to no avail thus far. I'll top up tonight and put in a bottle of the nulon total fuel system cleaner and see how we go. Keep the feedback coming guys .

Cheers,
Boojakz.

 

[sleepa]

I reckon you should give a set of new leads a go. I was driving a car which felt like it had less power, slightly rough idle, other than that, not much wrong, If you didn't know that type of engine before you'd think it was normal. But I chucked in a new set of Topgun's and the difference was amazing, felt like a new engine, I was very surprised with the results.

 

[Vt_vic]

you can try to go to a mech with a tech2 or holden they should point out any 02 faults but try some injector cleaner first

 

[danja]

There are so many things it could be, leads, sparks, fuel filter, O2 sensors, air filter, blocked cats, injectors, MAF, temp sensor, and probably a bunch I haven't covered.

I would start with the cheap easy ones, which don't hurt to do anyway like clean the MAF and throttle body (could be the cause of your rough idle), change air filter + fuel filter if they haven't been done for a while (though major service should cover both of these), run some injector cleaner, replace the leads if they are suspect or very old, same for sparks, O2 sensors will be on their way out around 160,000 if they are still original and would be worth doing.

Good luck

 

[boojak87]

Just topped up the tank with ultimate again and put in a dose of injector cleaner so we'll see how it runs in the next few tanks. The car has just clicked over 100,000kms but i just had the major of all major services that Holden offer and that's the 160,000kms one so they replaced the air and fuel filters and replaced all plugs, so they're off the checklist. I'm leaning towards a dead lead at this stage but we'll see how the injector cleaner goes first. Keep the feedback coming guys .

Cheers,
Boojakz.