1998 Ford Ranger P0174, P0306, and P0401 Codes - Solutions for 154,000-Mile Vehicle
I recently worked on my 1998 Ford Ranger with 154,000 miles. I've replaced the vacuum hoses and air filter, but the vehicle still shows persistent diagnostic trouble codes: P0174 (rich mixture in bank 2), P0306 (misfire detected in cylinder 6), and P0401 (exhaust pressure too low). The MAF sensor has been cleaned and is functioning properly. What other potential causes should I investigate to resolve these issues?
Begin troubleshooting with the P0401 code, as it often indicates a clogged or malfunctioning exhaust system component, such as a faulty catalytic converter or restricted exhaust flow. Check for leaks or blockages in the exhaust path and ensure all components are properly connected.