I've been dealing with this annoying issue on my Cherokee for a few weeks now where the engine seems to idle rough, almost like it's stumbling or missing slightly when I'm stopped at traffic lights, and there's also a noticeable hesitation when I press the accelerator from a standstill. It's not terrible, but it's definitely gotten worse over time and I can feel the car shaking more than it used to, which is starting to worry me a bit. I did a bit of research online and it seems like spark plugs are one of the most common causes of this kind of issue, especially if they haven't been changed in a while, and I honestly can't remember the last time they were replaced. I know that Jeep engines can be a bit sensitive to the type of plugs you use, so I want to make sure I get the right ones rather than just whatever the parts shop has in stock, because I've heard stories about people using the wrong heat range and ending up with even worse performance. I've been meaning to get this sorted for a while but I've been so busy with work and life that I keep putting it off, and now I'm thinking I should just get it done professionally rather than trying to do it myself and risking breaking something. A mate at work mentioned that if I can find a place that does Quick Jeep spark plug replacement, they can have it done in no time and I won't have to worry about whether I've gapped them correctly or torqued them to the right spec. Has anyone here had similar rough idle issues that turned out to be spark plug related, and did changing them make a noticeable difference to how smooth the engine runs? I'd also love to know if there's a particular brand or type that works best for these engines, because I've seen everything from standard copper to platinum to iridium and I'm not sure which is actually worth the extra money.