I have recently purchased an 03 SER spec v. To replace my beater mazda. Since purchasing the car it started running the p0300 random misfire code and the p0303 cylinder 3 misfire code. I have replaced the coils, plugs, injectors, fuel pump, Cam and crank sensors to try and fix the problem. Then after some more research I learned about the computer controlled throttle body that this car has. (Not impressed with that design nissan). So suspecting the throttle body I took it into a local mechanic who confirmed that I had a bad TB as well as fixing a vacuum leak I had. My mechanic was cool and advised me to replace the TB myself to save money and bring it back in later for reprogramming. So finally after getting all that done. The car definitely drives better. No hard starts anymore. And the idle doesn't surge up and down anymore. But I'm still getting a p0303 code. It still idles a little funny but way better and the car runs and drives well. Sometimes when you start to idle it will rev up to 2000rpm but then go down to 1000rpm and stay there. I don't know why I'm still running a code thought. Since literally replacing everything. I really just think it's a computer isue and nothing really wrong with the car. But I worry if I ever have to smog the car again that it won't pass.