VS Missing.

[TA 91 WA]

I'm sorry if this has been searched but I find mine a bit weird.

Also I did post this in the Dr. Bob part of the Pub but I thought if I post there then I might get a quicker result.

Today I took my 1996 VS Commodore (3.8) for a drive and when the temperature was half way, it missed under pressure (when foot was down). When I reached the speed limit and held my speed it was fine. When it was cold and under pressure it wouldn't miss. I put new plugs and leads in only 1000km ago. Would it be the coil pack or something simple like moisture in the leads? I did a error code check and it came back 12 which means its fine. Hope I have explained enough. I also cut the earth wire on the O2 sensor as well if that adds much.

Thank you.

Tom.

[apoc585]

im guessin by missed u mean miss fired?
when u checked, did u get 12 3 times? cos u have to wait for all three to make sure nothing is wrong.
why'd u cut the ground wire on the o2 sensor?

[TA 91 WA]

im guessin by missed u mean miss fired?
when u checked, did u get 12 3 times? cos u have to wait for all three to make sure nothing is wrong.
why'd u cut the ground wire on the o2 sensor?

Well it's got code 76 which is: Code 76 - Air/Fuel ratio variation between left and right banks

But I don't see that being the problem. Also I cut it because I was reading a thread somewhere about how it warms up or something.. I will link when I find it.

[Harvs82]

Check your leads and plugs again.... guarantee its either a faulty plug, lead or one of them not being connected up properly. Not sure about the cutting of the wires on the oxygen sensors too, I know that sometimes they have a bad earth, so its worthwhile checking that out. If you are getting a variation between the left and right banks, that will cause the engine to run too rich or too lean, but it won't really give you the missing symptoms though.

[TA 91 WA]

Check your leads and plugs again.... guarantee its either a faulty plug, lead or one of them not being connected up properly. Not sure about the cutting of the wires on the oxygen sensors too, I know that sometimes they have a bad earth, so its worthwhile checking that out. If you are getting a variation between the left and right banks, that will cause the engine to run too rich or too lean, but it won't really give you the missing symptoms though.

Yeah that's what I did with the bad earth so I cut it but yeah.. doesn't add up.

Is there a way you can test just the one plug or lead to see if its that single one or ?

[Harvs82]

Yeah that's what I did with the bad earth so I cut it but yeah.. doesn't add up.

Is there a way you can test just the one plug or lead to see if its that single one or ?

You can visually inspect each spark plug, check the gap on the electrode, as well as checking the porcelain to see if its cracked or not. In regards to the leads, yeah you can check them individually by using a multimeter and testing the resistance of each lead. Leads 1, 3, 5 are a specific range and leads 2, 4, 6 are also specific, ie different from the cylinders on the other side of the engine.

Do you have a Gregory's manual? It lists what the specifications should be for the leads, if you don't have one, let me know and I'll dig mine out and post up the figures.

[TA 91 WA]

You can visually inspect each spark plug, check the gap on the electrode, as well as checking the porcelain to see if its cracked or not. In regards to the leads, yeah you can check them individually by using a multimeter and testing the resistance of each lead. Leads 1, 3, 5 are a specific range and leads 2, 4, 6 are also specific, ie different from the cylinders on the other side of the engine.

Do you have a Gregory's manual? It lists what the specifications should be for the leads, if you don't have one, let me know and I'll dig mine out and post up the figures.

My one is a Haynes one so I'll check it out.