Please Help! Unsolved Misfires in Cyl 2, 4 and 6

[jboz1992]

Hi all,

Not long ago I posted a thread regarding random misfires in cylnders 2,4 and 6 in a 2006 VE SV6.

Since then the car has been in and out of my mechanics but nothing has been found, and theres reasons for that.

The random misfires come and go. It seems as tho every time I take it to the mechanic it stops misfiring. When my mechanic plugs is scan tool in it still reads 4 codes;

P0300
P0302
P0304
P0306

Allthough it is not misfiring at the time.

Since then he has not had time to look any further, So I have been reseting the computer by disconnecting the battery just to get around. It will run fine for 3-4 days with not a single hiccup after disconnecting the battery and then all of sudden (like clock work) start misfiring with CEL and running really ruff. The only way I can get it to stop is to disconnect the battery again.

It only seems to start misfiring after 3-4 days of normal driving and when I come to a traffic light when I stop and sit on idle. So it seems as though stopping at a traffic light or stop sign when at idle triggers the problem after 3-4 days of driving.

Does anyone have any Idea wat is going on, I tired of carrying a 10mm socket to disconnect the battery just in case it starts playing up.

Hope this makes sense.

Would really love some help, so throw some ideas and experience this way! PLEASE

[IGNITIONSV6]

Well the best way to start with misfire problems is change the spark plugs...and see if you can check the coil packs......misfires are usually something minor like that rather than massive problems. i'd be looking there first, have you changed the battery?

[vicarious]

i assume they checked the 02 sensors?

[peterrobo]

Because your problem (according to the fault codes you've given) appear to be restricted to the passenger side bank of cylinders (ie: 2, 4, & 6) I'd be looking at a dirty or corroded electrical connection on that side of the engine. If you've washed your engine down and haven't blown out all moisture it could also be moisture build-up in the spark plug cavities causing a short and misfire. Certainly check all electrical connections are clean and dry for the fuel injector harness as well as the coils that you have easy access to first. If you succeed in reducing the error codes you're well on the way to resolving the issue.

[RiCeY]

Failed catalytic convertor is a common cause of misfiring on one bank.

[greenacc]

Maybe your alloytech thinks it has AFM.
More likely what peter said, something to do with the passenger side. Is there a seperate power lead to each bank, or earth or fuel rail or faulty 'ECU' ? Next time its running well after you reset it try jiggling all the wires n jazz you can find on that side and see if you can trigger it..

[Sabbath']

Try checking the earth aswell, which is down below the coilpacks, on the side of the head.

[jboz1992]

Thanks for the replies guys.

I will certainly try everything listed here.

Other people have been throwing the words 'Fuel Pump'????

Is this possible? I spose they are my computerized now and the fuel pump could be failing with its electrical side of things

[RiCeY]

Fuel pump would affect both banks so no.

[peterrobo]

Hey jboz1992, did you get a resolution to your problem yet? If so, what was the cause of the problem as I'm sure many on here would like some feedback.

[Chaney]

Given that it runs properly after every reset, it might be a computer/sensor/monitoring related problem, especially given that the problem returns like clockwork once the computer leaves its closed loop parameters and starts 'tuning' itself. Rule out all the the common options between the two banks eg Fuel pump, maf etc and that leaves things bank specific things like 02 sensor, cam angle sensors, cam angle actuators, cat converter etc, maybe knock sensors (its has 2, not sure if it uses 1 for each bank, or both for both banks).

I just had a totally different problem where everything would run properly after a reset for an exact amount of time:
Ghost in the dash computer (fuel injector problem)!


My 2 cents anyway hope it helps.