When should I replace my Spark Plugs?

When should I Replace my Spark Plugs? Welcome to Mercie J auto care, where compassion and craftsmanship come together. I'm Rick Smith, master certified technician. As far as regularly scheduled maintenance, manufactures recommend you replace spark plugs about every hundred thousand miles. I personally think that’s a little bit long because the studies I’ve seen show that after about 60,000 miles, the energy it takes to fire spark plug goes up. When you have more energy requirements, that puts more stress on the coils. So that gives you an idea on the maintenance. Now as far as any other situation goes, we can’t really see a lot on spark plugs. We used to test them with an oscilloscope to see a problem. We used to be able to look at spark plugs, and tell whether they were too rich to lean, all that kind of stuff. The one thing that we can see on the spark plug is cracks. The cracks will almost always be vertically they won’t be horizontally. I’m gonna show you right here. Hopefully you can see really good the cracks in this spark plug. This was out of a 2016 Ford focus with a three cylinder eco-tech engine in it. Now two things can cause spark plugs to crack. One is during shipping, they can get handled poorly or dropped and that can crack the porcelain or the other is during installation socket goes on top, if we’re tightening it, and when we pull our socket over, it can crack it as well. So new spark plugs solved the P0 301 code on this Ford focus. Hope this has been informational to you. Until next time, safe travels and blessings to you.