I own a 1998 Chevrolet pickup with 198,600 miles. The engine is misfiring and has triggered a diagnostic code P0202 — indicating a fuel injection system fault in cylinder 2. I'm looking for guidance on how to diagnose and fix this issue effectively.
I'm not familiar with fuel injection systems that use a throttle body; I believe this applies only to certain models or configurations, so it may not be relevant to my setup.
The fuel injectors are located in the intake manifold and are referred to as 'spider' injectors. These are part of either a CPI (Cylinder Pressure Injection) or CSFI (Continuous Fuel Injection) system, depending on the model year and engine type.
Each fuel injector is individually controlled by the Powertrain Control Module (PCM), which is required under OBD-II standards for modern vehicles.
Even with a throttle body system, each cylinder still has its own dedicated injector. I didn't realize this before — it seems fuel does go directly to individual cylinders via injectors, not just through the intake manifold.
You likely have a CSFI (Continuous Fuel Injection) system, which replaced the older CFI in 1996. The large 'maxi' injector was replaced with six separate injectors that deliver fuel to individual poppet nozzles. In both older CFI and modern CSFI systems, these nozzles can become clogged or restricted over time. Many owners are upgrading from CSFI to MPFI (Multi-Port Fuel Injection) setups. Could you confirm your engine model? Is it a 4.3L V6? Also, do you have a digital multimeter for testing?
The most likely cause is a faulty cylinder 2 fuel injector. Other potential issues include wiring problems with the power feed or control signal, connector faults, or a malfunctioning PCM driver circuit. To verify, use an ohmmeter to test the resistance of the cylinder 2 injector and compare it to the other injectors. If the reading shows an open circuit (infinite ohms), the injector is likely defective.