I'm looking for a particular automotive problem that would not be serious enough to make a car inoperable, but would be easily identifiable by sound to someone who knew something about cars. The car in question is a used pickup truck; I'm not ever going to refer to it in any more detail than a) a used pickup truck b) with <whatever> trouble.
So, basically, here's the situation: Character A, who is kind of like me and knows nothing about cars, has a used pickup that has a <insert problem here>; as a result, Character B, who is quite car-savvy, can always hear when it's Character A pulling up, because Character B can hear the problem with Character A's truck. So, in the particular scene that I'm working on now, Character A fires up his truck outside, and Character B knows it's Character A firing up his truck, because, he thinks, "That <insert problem here> is unmistakable."
Does that make sense?
I've checked the memories, and I've spent the morning googling various combinations of "car" and "problem" and "sound", and everything I've found is either irrelevant, since it has to do with connecting your iPod to your speakers, or incomprehensible to me, since, as previously mentioned, I know NOTHING about cars.
Any help would be vastly appreciated.