Yes

 

Upstream sensor firewall side with green elec. conn.

 

I've done some searching on the forums.. but have found numerous instances where replacing the O2 sensor did absolutely nothing for the problem. "Fine for ~75 miles, then it came back on with the same code."

So do I replace it and just.. hold my breath and hope it works?

 

STOP!! Do NOT replace the oxygen sensor! 90% of oxygen sensor failures occur when the 24V heating element burns out, in which it has a set of codes indicating that the heater circuit has malfunctioned. The other 10% is the sensor becomes so damaged/clogged it no longer reports, in which it reports a No Activity code.

Insufficient switching means it is reporting to the ECU, however, it is staying to one side of the .450mv range and there is an underlying cause for that. If there were a vacuum leak prior to the intake manifold, but after the MAF, then both upstream oxygen sensors would be stuck on one side of the .450mv range and that would meet the qualifications for a System Too Lean code. My opinion is there is a vacuum leak, but a tiny one on the rear cylinder head, could be a pinched exhaust manifold gasket or a crack in the exhaust manifold. The EGR is also serviced off that bank so the EGR tube may be pitted/cracked, etc.

 

Insufficient switching means it is reporting to the ECU, however, it is staying to one side of the .450mv range and there is an underlying cause for that. If there were a vacuum leak prior to the intake manifold, but after the MAF, then both upstream oxygen sensors would be stuck on one side of the .450mv range and that would meet the qualifications for a System Too Lean code. My opinion is there is a vacuum leak, but a tiny one on the rear cylinder head, could be a pinched exhaust manifold gasket or a crack in the exhaust manifold. The EGR is also serviced off that bank so the EGR tube may be pitted/cracked, etc.

If both banks are affected by a vacuum leak, you get 0171 and 0174 codes.
If only one bank is affected, you get a code for that bank, but not both.

Insufficient switching, in my experience, indicates a lazy sensor that is in need of replacement.

Usual recommended service interval is 60-80k miles

 

84 Ford Man, Couldn't it be that vacuum boot that goes to the back of the intake that has 2 hard plastic vacuum lines running to it? I put plugs in a customers Sable, and when I was putting it back together that particular boot was swollen from oil. It wouldn't seal and kept throwing a CEL.

 

^+1

 

^ Cheers!

 

Wow. Thank you so much for the suggestions. I'll get to work on it.

 

I have to use my car tomorrow. It's still showing the code P1131.
What do I risk in driving the car "as is".
I don't risk causing any damage, do I?

 

No damage can come of it.