Vz missing at around 80k and underload. Diagnostic plz help

[Hatcher]

Hey everyone, this is my first post so any help and feedback is very much appritated Thanks. My miss's vz commodore starts missing at around 80k and when it' underload. Money is a bit tight so was hoping to try and get to the source of the problem without spending 2 much. I have a elm327 Wi-Fi device but since the engine light dosent come on when the cars missing it dosent throw me any codes. Does anyone know of a android app that will monitor the miss while driving along. Or can anyone describe to me step by step on how to diagnose it. I used to have a vp and only had to wack the multi metre on the coil packs and leads that were easy accesed. To what I've read so far it's a intake gasket everytime ya want to try and get close to spark plugs and coils . Would I be better of just replacing all coil packs and spark plugs and just start from there. My girl works everyday so time is not on my side I've only got night times to tinker with it and I got to make sure it's driveable the next morning. Any feedback and help would be much appritated. Thanks heaps guys

 

[Mick06 svz]

Find it odd you’re not throwing up a powertrain fault and limp mode is enabled.
You can just raise the plenum or take off necessary hoses and clips to just shift the plenum and manifold to the side keeping it a 2 piece and the plenum gasket is reusable as it uses a hard heat resistant plastic type. If you’re due for new plugs I would start there, mace sells the cheapest coils I believe and they’ve worked a treat for me.
Good luck..

 

[Hatcher]

Find it odd you’re not throwing up a powertrain fault and limp mode is enabled.
You can just raise the plenum or take off necessary hoses and clips to just shift the plenum and manifold to the side keeping it a 2 piece and the plenum gasket is reusable as it uses a hard heat resistant plastic type. If you’re due for new plugs I would start there, mace sells the cheapest coils I believe and they’ve worked a treat for me.
Good luck..

 

[Hatcher]

Thanks for the info Mick. I think I'll take your advice and start with the plugs now knowing the gasket is reusable and start from there. Do you know if u can check the resistance on the coils with a multi metre like you could on earlier models? Thanks again much appritaed

 

[Mick06 svz]

From my understanding and what the manual suggests due to the internal circuitry of the 3.6lt coils there are no resistance specifications that can accurately identify the values. If you had a miss on idle you could try and diagnose by pulling individual coils.

 

[rambunctious]

Thanks for the info Mick. I think I'll take your advice and start with the plugs now knowing the gasket is reusable and start from there. Do you know if u can check the resistance on the coils with a multi metre like you could on earlier models? Thanks again much appritaed

Don't count on the gasket being reusable.
If it is the original fibre gasket, then it is clean off and throw away.
The new gaskets are o ring style so can often be reused.
If the car has done 150,000 k's or more, do coils while you are at it, otherwise you just have to lift the plenum yet again.

 

[Mick06 svz]

Don't count on the gasket being reusable.
If it is the original fibre gasket

That’s interesting, my vz’s plenum gasket wasn’t fibre unless the previous owner had changed it over at 30k which would be unusual.

 

[gungazza]

when was the last service, plugs only good for about 40,000, I think ,I would start there, has the motor been washed ,I had a problem with that, I got a country car full of red dust, washed the engine ect, the engine light comeing on, eny way problem was coil pack rubber was stuffed don't know why,water had got in ,eny way six new plugs now ok

 

[rambunctious]

That’s interesting, my vz’s plenum gasket wasn’t fibre unless the previous owner had changed it over at 30k which would be unusual.

The 2 plenums I have removed were 06 and 07 builds.
Both had fibre gaskets which left half gasket on the plenum and half on the intake.
Once you have the rubber style gaskets, they can be removed/replaced more than once

 

[losh1971]

Sounds like its a problem with the TPS.