90% of defective injectors can be brought back to "good as new" We recondition thousands of injectors. The only time we can not bring them within spec is if the coil goes bad, or if the pintle valve is damaged or if the pintle valve seat is worn from harsh abrasive chemicles in the fuel (rare). Off car, flow bench testing and cleaning is the absolute best way to maintain your injectors. And at a fraction of the price of replacing them. For example, we charge $17 per injector (no charge if we can't bring the injector back into spec.) which includes replacing the small filter basket in the top of the injector, before and after test data, and new o-rings and pintle caps if needed.