How to confirm what the problem is.

Question

My husband just replaced an oxygen sensor after another code came up. The engine light came back on after a couple of days. It now says code P1131 for a Ford. Do you have any suggestions as where he should start to locate the problem? I appreciate any help you can be. He used an OBD II machine to get the code.

Answer 1

The first thing to check for is an intake leaks, broken/cracked hoses are a common problem due to the age of the car.

Also I would use 91 octane fuel from shell and a good fuel system cleaner, just in case there is a clogged fuel injector.

if that does not fix the issue, I would check fuel pressure should be (35psi-40 psi)