It's rare to find an auto repair shop that doesn't try to squeeze a few extra dollars out of you, especially in these tough economic times. The check engine light in my Acura had come on--only the second time it's happened in the 10 years of owning the car. The last time it happened, I ended up replacing my O2 sensor. It came on a few days after I recharged the K&N filter. Thinking it was the problematic O2 sensor, I dreaded paying another couple hundred dollars to replace it. I found CME Smog & Auto Repair on Yelp and was impressed with the reviews, so I brought the car in to get it checked out. A few seconds after I explained the situation, they told me to check the fuel tank cap for any hairline cracks in the rubber seal. From what they've seen, a broken seal caused 90% of the lights coming on. They told me to first tighten the cap beyond the three clicks, at least 7-10 clicks when the fuel level is between 3/4 to 1/4 full. If the problem is the cap, the light should go off by itself in a few days. I was pleasantly surprised. As soon as I went back out to the car, I checked the cap and found two small cracks in the seal. I left the shop and felt like a winner.

The next day I bought a new fuel tank cap and replaced the broken one, then tightened it to 7 clicks. A few days passed and the light had not come off. I brought it back a couple days later for an oil change and the technician ran a quick diagnostic and found that the check engine light may be attributed to cylinder firing timing being off. They told me that the fuel tank cap isn't the likely culprit. Great, I thought to myself. This was going to be expensive. I went ahead and scheduled an appointment to drop the car off the following week and was ready to drop the dough. Two days before my scheduled appointment, I had refueled the tank once since buying the new fuel tank cap. Low and behold, shortly after starting the car in my work parking lot, the check engine light disappears. CME was right, although it did take almost a week for the light to go off and a bit of a scare. - Michael C.