If you get only one code p1131 on your 1998 ford expedition would it be the o2 sensor bank 1 sensor 1 or can some other sensor-fault generate this same code.also is there any easy way to remove it?
If this is the only thing wrong then change it. If it comes back on then your mass air flow sensor could be sending screwy signals or the injectors for that side are not giving enough fuel. I hope this helps some.
Soak the sensor in penetrating oil first. Let it set for a bit. Disconnect then unscrew it. I removed mine with just a wrench. I did hit the ole knuckles once or twice though. It was really cranked on there.
I have a 1999 expedition and my computer had that same code and i had replaced the coil packs and plugs, and cleaned the pcv valve and the mass airflow sensor and the code was still there. come to find out my intake manifold gaskets were shot. i hope this is of some help.