I got a MaxiScan MS509, great peace of kit for just getting fault codes and resetting the ECU, only cost me £40, and payed for itself first time out of the box, sense then I have used it a couple of times now with Injector problems, it found the fault code, and gave me simple advice, like what cylinder the misfire occurred on, so I new which injector to change. And on top of all that it has advanced feature like live scan of some of the sensor from the ECU, and you can log this data, and transfer over to a computer.