Dear Tom and Ray:
I have a 2003 Subaru WRX that has recently been "sneezing" at irregular intervals. The sneezing sound is accompanied by what feels like a loss of power. The sound seems to be coming from the driver's side, under the gas pedal. It is quite audible from outside the car as well. Sometimes it occurs when I'm just pulling out, other times when I'm well under way. It doesn't seem to matter what gear I'm in, and it doesn't happen with any consistency. Got any ideas what might be wrong?
TOM: Sounds like it's allergic to something, Lucy. Have you tried putting Claritin in the gas tank?
RAY: Actually, it sounds more like YOU'RE allergic to something, Lucy: tune-ups. What you're experiencing sounds like a classic engine misfire.
TOM: Intermittently, one of your cylinders is not firing, and that creates a brief interruption in power. You feel that, and you also hear the engine chug a little bit. Or sneeze, if you like that description better. When Kleenex decides to sponsor our column, we'll start calling it a sneeze, too.
RAY: Since the spark plugs and spark-plug wires on this particular car are really crammed in there and hard to reach, my guess is that they haven't been changed in a long time, if ever. And they're the most likely cause of an engine miss.
TOM: Eventually, this condition will trigger your "check engine" light to come on. But even if it's not on yet, have your mechanic "scan" the car and see if the computer has stored any codes. If there's a code in there, it'll tell you which cylinder is misfiring.
RAY: But even if it's only one cylinder that's misbehaving, it's probably time to change all the plugs and wires. If one's gone bad, they're all ready to go bad.