QuestionOn March 16, 2006 I took my 2005 Hyundai Accent 1.6LDOHC in to the dealer for a Check Engine light problem (36k miles). The codes were P0301 and P0303. The mechanic said I had a spark plug wire shorting out. So he replaced the wires. He also stated I needed my spark plugs replaced since they were not replaced at 30k. He had already taken one out- it looked like a new one. I told him no since I had just driven a Ford Focus for 150k and it still had the original plugs. Besides his charge was $130 to replace 4 plugs. He also stated I needed a Fuel induction service. I allowed him to do this costing me $132. It seemed to run good till the other day when it sputtered when I first started it up. Now the Check Engine light is on -3 months and 8k later! I haven't taken it in yet but surely spark plug wires should last more than 8K.
Exactly what do these codes relate to?
AnswerP0301 indicates you have a misfire on cylinder #1 and P0303 indicates you have a misfire on cylinder #3. The codes don't indicate anything about the cause of the misfire. The technician must perform further diagnosis to determine the cause of the misfire.
Here are my thoughts:
1. The mechanic was exactly correct to recommend new spark plugs. The recommended maintenance interval is 30,000 miles. While the plug may have looked new to you, I can guarantee that at 36k, the electrodes were well worn. The spark plugs in your vehicle aren't platinum or anything else that has a long life span.
2. The induction service probably did little more than vacuum money out of your wallet. Rarely do intake deposits reach the point where they affect the engine's ability to run properly.
3. If you're in the U.S., your vehicle is still covered by the manufacturer's warranty. Of course, this won't cover the spark plugs, since they were due to be replaced at 30,000 miles. This also won't cover the wires installed by the mechanic if they're any brand other than Hyundai.
