I use mini cooper for once or twice weekly drive. The spark plugs of the mini cooper R56 goes bad on this moderate use every year!
What is the reason for this? I obtain genuine spark plugs and the car starts wobbling and sluggish in picking up acceleration, in about an year telling me that spark plugs needs to be changed.
I have to press full throttle so engine revs up fast eliminating the wobble and sluggish acceleration.
Per comments , fuel is leaded ; That opens a Pandora's box of problems. Tetraethyl lead was accompanied with bromine to scavenge the lead compounds so they would not foul plugs, etc, so fast. Also , I expect any location allowing lead today also has high levels of sulfur permitted. There is also damage to the plugs where you can't see ; deposits between the porcelain and the steel body are leaking some ignition spark energy giving a weak ignition spark. Cleaning the plugs is only marginal help. Using leaded gas , I think your best option is do what we did in the old days, get new plugs every year. I am not certain but I don't think platinum plugs is a solution although they may be better
It's always recommended to use spark plugs listed in owner's manuals. To use other than factory spark plugs makes you the Beta tester requiring knowledge of plug type, heat range, plug gap setting, etc. If you are using OEM spark plugs and wear or fouling occurs then this isn't a plug issue. Although most vehicles require less maintenance, replacing spark plugs, cleaning throttle bodies, replacing air and oil filters are still maintenance chores either a diyer performs or pays a dealer or repair shop to perform. Owner's manuals always suggest maintenance intervals to ensure optimum performance from our vehicles. Ignoring or forgetting maintenance introduces problems either sneaking up slowly or immediately. Servicing also allows one to see if any unusual wear occurs like a ruptured rubber hose or leaking fluid.
Using your car only once or twice a week would be considered light duty use, not anywhere near moderate use like daily driving. Severe use would be Ubering or delivering pizzas/fast food daily.
