Hello, so I have a 1999 Ford Expedition, 4.6l, 195k miles. Yesterday after waiting way too long to do so I swapped out the intake manifold gaskets, changed all plugs and wires, replaced the egr valve and solenoid, cleaned out the egr ports in the throttle body and replaced the boots from the throttle body to pcv valve. This engine still has bad exhaust manifold leaks on both sides but I didnt get to that yesterday.

After fixing all of the misfires, and egr codes, I was driving all day with no issues or ses light until late tonight I left for the store and about 3 minutes into driving the ses light comes on and I got to the store, used my scanner and it says P1151-Heated oxygen sensor bank 2 sensor 1 switch point indicates lean. The vehicle has never had this code before.

Now Ive read other posts with this issue, but Im posting because none of them that Ive found have been after any work like this performed. Could it be a vacuum leak at the intake manifold gasket? Or would a bad sensor read that way? I didnt think so but im not an expert. Thats what Im leaning towards but just wanted a second opinion. Especially since i have yet to see anyone suggest it. Thank you for any help!

Ps i have a scan tool that can show live data if that would help too.

 

The live data , both at idle and 2500 RPM if you can.
I don't know about the expert part, but hopefully one of them will jump in.


What would be interesting would be the long and short fuel trims, O2 rdgs and a few others.

 

Okay, and am I looking at the live data of the o2 sensor that is throwing the code?

 

Can you post those data PIDS here for us to examine?RPM-fuel trims-all O2 readings etc. The more info you can provide the better.

 

Well I finally found a minute to go out there and get that for you, but now the light is off..? I drive around for about 20 mins and it didnt come back so maybe it was just a fluke thing..if it comes back ill be right back here! Thanks for replying anyways.

 

Sometimes we just get lucky, thanks for the update.