Intermittent misfire at idle

[commodore665]

hey guys
I’ve got a question, now and again, my VZ SV6 has a misfire at idle , it runs a bit rough at revs , I’m thinking dodgy coil , the plugs were changed at last service. If switch off and re start it’ll usually run ok
Any ideas or thoughts are welcome

 

[gungazza]

eny codes

 

[commodore665]

eny codes

Not yet scanned ,but system check runs OK

 

[PAUL3T]

Could be coil-packs, could also be a lot of other things. If there are no codes and it does it once it's at operating temp I would start with coils. They can be easily checked by running the engine and removing the plastic engine covers. All of the coil-packs can then be reached. One at a time disconnect each coil-pack plug and the engine should start idling rough. If there is no change you have found the dead coil.

I recommend getting it scanned first however, if it's only a slight miss it could just be a sensor.

 

[commodore665]

Could be coil-packs, could also be a lot of other things. If there are no codes and it does it once it's at operating temp I would start with coils. They can be easily checked by running the engine and removing the plastic engine covers. All of the coil-packs can then be reached. One at a time disconnect each coil-pack plug and the engine should start idling rough. If there is no change you have found the dead coil.

I recommend getting it scanned first however, if it's only a slight miss it could just be a sensor.

Thanks mate , it only happens off and on , not all the time , twice over this weekend, before that over a month ago

 

[PAUL3T]

it only happens off and on , not all the time

I would be leaning towards sensors then. Wouldn't hurt to buy some MAF cleaner and give that a good clean. Oxy sensors should through a code if they are the culprit.

 

[commodore665]

I would be leaning towards sensors then. Wouldn't hurt to buy some MAF cleaner and give that a good clean. Oxy sensors should through a code if they are the culprit.

I’m going to take it in this week to my mechanic, probably get it scanned , MAF was cleaned recently , which is why I’m thinking coils

 

[stick3]

the brother vz started to run rough and went into limp mode he just cleaned the throttle body using throttle body cleaner and that fixed it

i did mine to it was filthy when i took the pipe off to replace the serpentine belt also did the mass sensor using the correct cleaners

 

[Fu Manchu]

I was surprised to read Holden info relating to accessories on the serpentine belt. It states that worn or out of balance pulleys can cause a random misfire. Might pay to have a squizz at that.

 

[commodore665]

I was surprised to read Holden info relating to accessories on the serpentine belt. It states that worn or out of balance pulleys can cause a random misfire. Might pay to have a squizz at that.

Good call , would never had thought about that