98 Jackaroo 3.5 petrol

I have the same vehicle with 247000 on the clock and have always suspected that it has had a slight misfire but I can not verify this as it is only just noticable - bit like I might be imagining it. I can only guess that you have the right plugs - for memory these are the expensive (but good) ones that last around 100,000. I have heard that the throttle body may have been an issue in these models but am unsure if this is your problem. As these types of problems are a rareity, you may have to consult with a Holden dealer as they may have had better experience with these things. Good luck - I also have a Jeep but I use the Jackaroo for work or knock around purposes - Jeep dealer only offered me $5000 for it so it is worth far more than that to me. Great old bus still in really good condition.