Rough acceleration and vibration in '95 VS???

[samd]

I recently bought a 4-speed auto V6 '95 VS Commodore with only 180,000km, totally straight and nanna driven all its life. There are just a couple of things I want to know so I can fix it;
1) only in foward gears (not reverse, park or neutral) it makes a vibration when stopped with the brakes on, it sounds like its coming from underneath where the gearbox connects to the engine. I've read that they can have issues with torque convertors??
2) when accelerating, it feels rough like it's miss firing or something, mainly at low rpm (0-2500ish) and it goes really well past that.

I will check the plugs, leads etc. It would be good to know if the two issues are related and if anybody can tell me any more about what I'm dealing with, it would be greatly appreciated.

 

[Brett_jjj]

First up try checking for any logged error codes.Heres a link to a post that explains how to do this simple test,and if you scroll down near the bottom of the posts in this link,theres also some helpful pics..
---https://forums.justcommodores.com.au/threads/checking-error-codes-vr-vs-revised.22307 ---

The plugs and leads are also a good place to start and should be replaced,even if they still "look" ok..

 

[m62vpute]

I would say to fix problem 2) first as i think it may be a major factor with your vibration issues, As brett says check for any logged error codes then plugs and leads.

 

[hako]

If you don't find anything when you do the above tests, maybe you should read the original road tests on VN to VS Commodores - all noted harshness when under full acceleration. There have been many threads about this with many cures offered and sworn to work but don't always. Mine has had new engine mounts, rear control arms and uni joints and still feels like a 747 taking off with the pedal to the floor....and that has not changed in 7 years of ownership and over 200,000km.

 

[samd]

Thanks for the suggestions everyone, I'll check it out tomorrow. I think the vibration may actually be from something in the suspension or an engine mount as it sounds like it's from the front left hand side

 

[family fix it man]

My VS wagon has gone through a few COIL PACKS in its time with me. Easy test if you have limited time/ tools, take off 1 lead at a time from the coil. If bright blue sparks jump down the side when you start the engine, then the coil is O.K. If no or weak spark, the coil is probably R.S. This causes the engine to miss bad at low rpm but is harder to notice when you get the revs up. Sounds like you have bigger problems, but start with the easy ones and work up :idea3:

 

[family fix it man]

My left front bushes are shot and make a bad noise too, don't worry it is on my list of things to fix :beer chug:

 

[RX25SE]

Easy test if you have limited time/ tools, take off 1 lead at a time from the coil. If bright blue sparks jump down the side when you start the engine, then the coil is O.K.

I would NOT recommend this test.

Apart from the coil trying to bite you, sending 30,000 volts into the DFI module may upset it somewhat. Not to mention that it could leak down one of the DFI wires to the PCM.

ALWAYS correctly ground a secondary (coil) voltage. Use a spark tester or an old plug welded to an alligator clip. (see below)