1998 Ford F150 P1537, P0401, and P0176 Trouble Codes - Solutions and Fixes

Model: 1998 f150 Fault Code: P0174 Posted: 2014-11-11 16:26

I own a 1998 Ford F150 with a 4.2L V6 engine. I'm consistently receiving diagnostic trouble codes P1537, P0401, and P0174. I've already replaced the EGR valve, but the issue persists. Notably, when I use higher octane fuel, the P0174 code disappears temporarily. This suggests a possible fuel-air mixture or sensor-related problem. What steps should I take next to resolve these codes? Are there any other components I should inspect or replace?