Very strange (but random) engine behaviour in a VXII V6 - almost stalling

[webbiegareth]

Guys & Gals,

I need some help with my 2002 VXII Commodore, the standard V6 ecotech model. It's a very strange problem and I have no idea what's wrong, though I suspect one of the onboard computers.

Basically, when you're driving at say 60km/h, and you take your foot off the accelerator, the RPM's will slowly drop down to a bit over 1000rpm as the car cruises/glides along. At least that's what my car normally does.

But every few months my car will behave a bit strangely. It'll accelerate fine, but if I take my foot off the accelerator, the rpm's will dip down BELOW 1000rpm, to what looks like a standard idle speed (750rpm?). The engine feels like it's cut off, even though it's not. If I jab the accelerator, the rpm's will roar back up, then if I take my foot off, it'll drop back down to the idle rpm speed.

If I'm slowing down for traffic lights, or to park in a car park, when the car is at say 5km/h, and I take my foot off the accelerator to "glide forward" (i.e. to turn into a car parking space), the engine starts to stall and I quickly put my foot on the accelerator and then the engine kicks back into life.

To fix it? I turn the car off and back on again - and it's back to normal!

It only does this once every few months, and all I have to do is pull over, turn the car off and on again, and it's fixed. But what the hell is the cause of this? I suspect a computer only because I just need to turn the power off/on and it's normal again.

Has anyone experienced this before?

[VT_SS]

Not sure there mate but if its a standard car like you said there is no mods to iliminate.I take it you have gone over the engine bay checking for loose wires and wot not.Baring all that i would fork out the money to get it scanned buy your mechanic and not a holden dealership they will bend you over mate unless you know some one there.

[webbiegareth]

The only mod I've made to the car is modified the air intake snorkel (cut a hole out near the front to get air from the radiator area).... that's it. I did that when I bought the car though (back in '02), so that's not the cause. Other than that the car is fully stock, original everything (bar the usual stuff like leads, sparks etc).

My mechanic has the gear to read the codes so I'll get him to rescan the car at the next service and see what it shows (he'll do that for free as part of the service thankfully). It's a damn strange problem though! It happened again last night and almost stalled in the car park, so I figured I'd post it here to see if anyone else has ever experienced it.

If we can't figure it out, not a huge issue as it really doesn't happen that often, and I know when it's doing it (by the way the rpm's dip so low), so I can easily just pull over, turn it off, turn it on again and be on my merry way. But it'd be cool if I can fix it though

[VT_SS]

Well it sounds like you have a good mechanic so lets hope he can sort it for you. But would be a good idea to invest in a proper CIA i know you said that it was done a while ago but your probally sucking in more hot air than cold air. MACE do a good CIA, after this issue is fixed good luck oh by the way dont know if you drive it in drive if so try slappin it into 3rd bring the revs up a bit it should sit on about 2000rpm or just under at 70-80kph anything over that put it in drive.