Engine Misfiring - Help

[Poorunsdownhill]

Hi guys,

Recently my MY10 VE Commodore has began misfiring. I’ve had a few codes thrown every now and then but nothing major like this till now. It’s got 200,000kms on the clock.

6 months ago the car started throwing throttle body idle position not learned codes. It didn’t impact the car and I’ve have the throttle body a clean every now and then and it was all good.

Both Cats have been throwing codes too about being under threshold but my mechanic told me it wasn’t worth replacing and it shouldn’t impact my car day to day.

Ive now started copping misfires. Initially it was Cyclinder 6 so I took it to the mechanic and they replaced all coils and plugs. It went away for a week and now it’s throwing Cyclinder 3 misfire.

It seems that every time I start the car I’m getting more codes. Now I have PO303, C027B, U0100. Yesterday I had PO430, P0300, P0303, P0155.

I can see that 2 of my O2 sensors are pulling .45v which I believe is normal and the other 2 (both sensor 1 on bank 1&2) are pulling .05v and .66v respectively.

Could replacing the O2 sensors fix the misfire issue?

As for the new codes today, I have no idea where they have come from. It’s got me very confused.

Any help would be appreciated

Thanks alot

 

[krusing]

Not sure of the O2 Sensors, at this stage,
Possibly its got a lot to do with the misfiring,
Could even be the fuel is contaminated,
With all the issues happening at once, its now a process of elimination.
How did you get the Code history ?
Assuming you have a OBD2 scanner ?
For what is worth, first port of call would be get new plugs, and new coils,
Then you can eliminate the common denominator,
because if the spark plugs don't work correctly,
Nothing will work correctly.

After replacing the Plugs and Coils,
Scan it again, make a notes of the Codes, or record them. Current/ Present & Not Present
Then Reset all the Codes,
road test it,
and see how it preforms,
if it drives ok, try it for a few days,
then Scan it again, to see if there is any historical DTC's [misfires that didnt activate the MIL]
that are not Present. [aka: Not Active]

It could even be the Alternator, with a low Charge voltage, with the systems shutting down.
Maybe a Bad Ground/Earth Connection ?
Fuel Injectors faulty ?

Again, needs to be scanned correctly and check the live event logs.

You have listed you are in "Victoria"
But where ?,
as a JC Member maybe able to assist you if you indicate a approx. location. [Town or Suburb]

 

[krusing]

PS: If you not sure of the Codes, you can check on this page

https://www.obd-codes.com/search/?cx=006282753923640923292:bsyyn-_1vle&cof=FORID:11&ie=UTF-8&q=P0303&sa=Search

and here

https://obd2pros.com/dtc-codes/

 

[Fu Manchu]

I had a similar story with my VZ. The problem was the cats. They checked out with a laser thermometer, but as soon as I changed them, all the codes went and the car was happy again.