club.liberty.asn.au

When in neutral and increasing the revs slowly from idle to about 1500rpm there is a noticeable rough running that can be felt through the car and sounds a little like a misfire. Hold the accelerator at this point and the revs hunt up and down by about 200rpm. Depressing the accelerator further and increasing the revs to 2000rpm then the rough running disappears and the engine sounds perfect!

I've never noticed it when driving accept when idling in gear on a hot day the revs tend to hunt quite a bit and it's not related to the air con clutch kicking in.

Any ideas?

Thanks

Avcs issue: log the vvt angles for exhaust and inlet during the described condition and during freeway cruise in different gears. Clean or replace affected ocvs and check replace or delete banjo filters....

If not check plugs, coilpacks, waste gate actuator, inlet and zorst leaks. Etc...

dirty injectors. pretty common on the old my04. subi spray in the fuel rail for 30 mins fixs this!

Matt.

Pretty much have the same issue with our 04 GT.

I've had the injectors removed and ultrasonically cleaned, plugs replaced, 02 sensor replaced twice, AVCS banjo filters removed and the solenoids cleaned, had a workshop check for vacuum leaks, replaced the air box and MAF sensor and I've swore and cursed at the fuc*ing thing till I was blue in the face and no one can tell me what the problem is or how to fix it.

So I'm real keen to hear if you do find out what's causing this particular issue, cause I've seriously done my head in trying to figure this one out

Cheers,
Rusty.

tune more fuel in...??
sounds like touch lean?

J

jslayz wrote:tune more fuel in...??
sounds like touch lean?

J

J
I really don't think it's a lean condition, as it's using more fuel than our previous VS V6 Commodore.
Cheers,
Rusty.

Log that avcs

bigBADbenny wrote:Log that avcs

Tony's already sussed this out Ben and there was no problem.

Cheers,
Rusty.

04GTLIB wrote:

jslayz wrote:tune more fuel in...??
sounds like touch lean?

J

J
I really don't think it's a lean condition, as it's using more fuel than our previous VS V6 Commodore.
Cheers,
Rusty.

Reckon lean if all else of good.

Afr sensor replaced when?

jslayz wrote:

04GTLIB wrote:

jslayz wrote:tune more fuel in...??
sounds like touch lean?

J

J
I really don't think it's a lean condition, as it's using more fuel than our previous VS V6 Commodore.
Cheers,
Rusty.

Reckon lean if all else of good.

Afr sensor replaced when?

J.
Don't really understand what you mean by "Reckon lean if all else of good"
The sensor was replaced for the second time about 3 months ago, with absolutely no change to the issue.
Cheers,
Rusty.

04GTLIB wrote:Matt.

Pretty much have the same issue with our 04 GT.

I've had the injectors removed and ultrasonically cleaned, plugs replaced, 02 sensor replaced twice, AVCS banjo filters removed and the solenoids cleaned, had a workshop check for vacuum leaks, replaced the air box and MAF sensor and I've swore and cursed at the fuc*ing thing till I was blue in the face and no one can tell me what the problem is or how to fix it.

So I'm real keen to hear if you do find out what's causing this particular issue, cause I've seriously done my head in trying to figure this one out

Cheers,
Rusty.

If you can get some logs with a tactrix cable then we can lend a hand... the OP (ie matt linegar) sounds like running lean/usually caused by a boost leak. If you connect with a laptop we'll quickly see if that's the issue.

It's very unlikely to be the AFR/O2 sensor, because the car won't go from idling badly to idling well of a sudden.

You have to think "why is it good at above 2000 but not below?", which also makes the plugs and injectors very unlikely.

Get in there and log for what's changing when you click over 2000, what are the AFRs like in both regions, other symptoms - how does it drive etc. If it's a boost leak a simple Learning View should show it up.

The issue is usually pretty simple to fix, but it can be a real test of character trying to find what it is. Good luck and if you need more advice/details let us know!

Have the spark plugs coils and leads been checked?

Cam sensors are another culprit.

And log me the inlet and exhaust vvt angles please during the described issue.

Just to clarify - to the OP, matt linegar - check your vac lines, it sounds like you've a simple boost leak and/or one of your vac lines has popped off and is messing with your AFRs letting it run lean at idle/that particular engine load.

To 04LIBGT - I wrote most of the previous post in reply to your case.

Cheers for all of the responses guys. The log will have to wait a fortnight, as I head back out to work tomorrow.

My apologies to the OP matt_linegar for clogging up your thread, just wanted to let you know I've had similar issues and I've been going around in circles for quite some time now

Cheers,
Rusty.

Hi guys.

Ha the first long drive out of the city today. Also noticed a stuttering/ misfire around 2500rpm in 5th with slight acceleration. Other than that she driving well.

Will investigate under the hood ASAP. Does anyone know somewhere on the lower north shore in Sydnet where I can get it plugged in to see if there are any odd readings?

Matt