Out here in the cornfields, we see a little bit of everything roll into the shop—trucks, cars, SUVs, you name it. Most of them run on good old gasoline engines. And while each job has its quirks, there are a few issues that come up time and time again. So we figured we’d take a few minutes between oil changes and carb cleanings to share what we see most often—and how you can stay ahead of the worst of it.