Vz Misfire!

[christo]

Hi there, I have a 99 VZ V6, 105k, which is misfiring intermittently. It is smooth after startup for about 30 seconds then misfires and idles rough, if I drive for a bit the problem is still there but goes away from time to time when idling. (but never completely!) No error codes or messages at all. Has anyone got any ideas? Would greatly appreciate it. I'm off to check hoses. Thanks!

[PaulSV6]

99 VZ??

When where the spark plugs last changed? Could also be a bad batch of fuel you've picked up, run some Wynns injector cleaner through it if thats the case.

[Sean880]

If you have a faulty plug lead or leads you will also experience a miss problem.

[calay]

i had that with my calais not too long ago - a couple of weeks after i changed the plugs, and a day after holden serviced it...sus much???

i couldn't work out if it was the fuel or coil packs but after loosning and re-seating all the coilpacks it was fine... it was very weird and annoying tho

[christo]

sorry i meant 06 VZ! Thanks for the help, will go round the plugs & leads next.

[PaulSV6]

If you have a faulty plug lead or leads you will also experience a miss problem.

VZ's dont have Leads, they have electronic coil packs. In place of the older leads & distributor cap.

[bigdaddycool]

It's probably a vaccume leak or your spark plugs, check your intake manifold bolts are tight enough.

I had this once when changing my sparkies...

[baracuda]

i got the same prob and diagnostics showed something wrong with injector circuit on cylinder 6 ? still dodgy fuel i dunno?

[christo]

Thanks for the replies, just changed all the spark plugs and no difference. Perfect idling for about 30 seconds when cold, then rough idling & acceleration most of the time. Will keep testing thanks......

[PaulSV6]

Have u tried process of elimination. Unplug each injector one at a time & see which one makes the difference or no difference

[baracuda]

well found out what my problem is. need a new ECU.

[christo]

Thanks for all the replies, the VZ is finally fixed! I eventually gave up and took it to Ultratune, coil pack #2 was dodgy and they replaced it. Runs perfectly again!

$132 for the replacement coil, $130 for labour and $60 for a new metal inlet gasket. So about $320 all in, not a bad result I guess (Holden quoted me $195 for just the coil!)

Now I hope the other 5 hold out........

[mattsv6]

hey mate,

If another one fails, buy these and ill show you how to replace them all yourself without needing a new gasket. Total cost = $225 for 6 new coils.

GENUINE HOLDEN COMMODORE VZ V6 BOSCH COILS 3.6L - eBay, Other, Car Parts, Accessories, Cars, Bikes, Boats. (end time 15-Apr-10 13:27:26 AEST)

[Trent L]

Yep. Just picked half a dozen coils from the same Seller, together with a set of Bosch Platin plugs and a pair of front O2 sensors.

That should give my VZ a tickle up & help with the fuel consumption.

Just got to grab the metal inlet gasket for a VE and figure out how to fit 'em up.