Hi, I've been reading TONS of posts online and I'm noticing that a lot of other people are having similar problems as I am. This is a long post, so please bear with me.
I have a 2004 Sentra with 133,000 miles.
Yes, I know that's a lot, but I drive about 90-95 miles a day to work (round trip) and then if I want to do anything remotely fun on the weekend, well that adds more mileage. Anyway, I've been having a problem with my SES light and the P0303 code.
In August my SES light came on and stayed on for a few days. I took it to AutoZone and they did their computer check scan thing and told me it was code P0303 and recommended changing the spark plugs. So I bought new spark plugs and had them changed. The light went out for a few weeks. Then it came back on. I had to wait a few days to make an appointment with my local Nissan dealer and in the time I was waiting for my appointment, the light went out. I took it anyway and they said sometimes the code can be left in the system even if the light is out. So they did their scan too and told me the same thing, P0303 and suggested changing the coil and stuff for Cylinder 3. So they did it, the light went out and all was fine. For a few weeks. From the end of August until now, the light has gone off and on and off and on and off and on, you get the point! From time to time, I will get a sputtering feeling when I start the car. But once I give it gas and I get moving, it's fine and doesn't do that anymore. Looking for an answer once and for all, I took it to a different Nissan dealer. They ran the diagnostic test, gave me the same code. But at the same time, they tested it for any fuel pump, head gasket, spark plug issues and said they couldn't find anything. Said the only other issue would be electrical, but that could get really expensive and they don't want to fix it if they don't know 150% that it's the problem. The light has been out since my appointment last week, but yesterday it came back on again. And today when I drove to the grocery store and accelerated, the SES light decided to do something completely different and blink for less than 5 seconds. I thought my car was going to explode or something, but it stopped, the light stayed on and the car feels like it drives fine.
It's like my car is mocking me and saying "ha ha, I have a problem and I'm not going to tell you what it is, and I'm going to make it really hard to diagnose so when something does happen you're going to get stuck with a monster bill!" I'm SUPER frustrated with this and was hoping someone had some advice to offer.