It happens often and when you least expect it. You are driving down the road (minding your own business) and your engine begins to shudder for what seems like no reason at all, and then corrects its self. The symptom will be fleeting and pass quickly, but will inevitably return. The PCM (powertrain control module) is not likely to have generated a DTC (diagnostic trouble code) to help point a you in the direction of the failed component, so you start with the fuel filter. Right? Well chasing wiring concerns is no easy task. The symptoms may mimic that of a bad injector, poor fuel volume or quality, or even the turbo charger its self. With a little luck the problem will persist long enough to catch it in the act.
With out this insight an individual may have replaced an injector confidently being a know problematic component. It is of the utmost importance to eliminate a circuit failure before any hardware is replaced. A small investment in time will save untold amounts of money in parts or repair. Parts stores don’t like to return “test” parts.