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VR 3.8L running rough


New Member
Feb 24, 2019
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VR Commodore Utility 3.8l AT
Good day people,

Let me start by saying thank you to everyone who posts and comments on this forum. I have been using this resource to keep my old VR running and it has been invaluable.

As much as i have searched through old posts, I have not been able to find the solution to fixing my car.

The problem: She was running rough and had little power when I went to accelerate, feeling sluggish at low revs, misfiring and surging.

Attempted solutions:
Replace spark plugs: seemed to make the problem more noticable
Replaced 2 x ignition coils which seemed not to be firing properly: problems decreased
Crank angle sensor: decrease in problem but still noticable
Fuel filter: no change
Ignition leads: noticeable difference yet problem is still there

The sluggishness and misfiring seems to be worse when the engine is warm, not so much first thing in the morning (4:30am)

I would also like to know if replacing the DFI module will help or if there is a way to diagnose that to be the problem.

It's not throwing up any error codes (apart from 12, all is well) and I'm at a bit of a loss. My final step will be a mechanic but I have a funny feeling it'll cost me a small fortune. Seeing as the ute only cost me $1300, I'm a touch reluctant to spend money but it is my only means of transport and i cannot yet afford another. Classic rock and hard place scenario.

Any information you can send my way would be greatly appreciated.

Thank you for the time to read my post and happy driving