2005 Kia Sedona P0172, P0175, P0302, P0510 - Misfire, Rich Mixtures & Idle Issues
My 2005 Kia Sedona is consistently showing fault codes P0172 (Rich Bank 1), P0175 (Rich Bank 2), P0302 (Cylinder 2 Misfire), and P0510 (Idle Air Control Circuit Malfunction). The P0510 code includes a 'P' suffix, which indicates it's pending — meaning the fault may set again after further testing. The P0302 code was initially caused by a failing coil-over-plug with visible arcing. I replaced both the spark plug and coil, but the misfire has not fully resolved. P0172 and P0175 have persisted for years despite multiple component replacements including the MAF sensor (replaced twice), TPS, and air filter. The vehicle starts and idles smoothly, accelerates well from a stop, but exhibits poor throttle response above 35 mph — RPMs increase without corresponding speed gain. There is noticeable hesitation when accelerating. I previously replaced the TPS and MAF sensor (last replacement about two years ago), and during those instances, the vehicle entered limp mode. This time, the behavior feels different. What should I check next to resolve these persistent codes and improve performance? Is it possible that fuel injectors are leaking or that the air intake system is clogged with incorrect filter use?
Which engine model? The 'P' suffix in P0510 indicates a pending code — it will set again after further diagnostics. P0510 points to an idle air control circuit malfunction. If you've already replaced the TPS, next step is a thorough wiring inspection. For P0172 and P0175 (system rich in Bank 1 and 2), clean the MAF sensor and ensure you're using the correct Kia-approved air filter. Also check for fuel injector leaks. Is the P0302 code still active? Confirm the spark plug is properly installed and functioning.