Chasnging oxygen sensor 2000 ford expedition

Install the new Oxygen Sensors

Google the P1124 & read up

Type: Ford OBD P1124

Could be the upstream oxygen sensor is faulty and is causing a lean code, have someone with a scan tool watch all the oxygen sensors. compare the 2 front ones and make sure they are fluctuating properly

What brand did you install? If you installed Bosch, then that would be a problem

Okay, when you changed the Number 2 plug, did you also change the wire? Have you checked the Injector seat for a leak? Do this by spraying Choke cleaner on it while engine is running to see affect on RPM.

Check for Intake gasket for leaks. Clean the MAF sensor with safe Electric cleaner. If still no help, on some Fords there was a groove under the Airhorn gasket that needed periodic cleaning. Its 8 bolts and a $10 gasket.

Put on a pressure gauge at Injector rail and see if fuel pressure drops on acceleration. You can do a cylinder balance test Electronically and see if compression is a problem. Code 302 is a misfire on the #2 cylinder.

Would like to know outcome and if this is the DOHC engine with Cam Phasers.

You need a special socket for oxygen sensors from any store. There are total 4 two on one side and the two on the other side (Driver n Passenger) Try to put some WD40 so that you are not break the exhaust pipe otherwise more money. Try first the driver sides and than passenger one. The one on the passenger side under the hood is very hard i also cant get it it needs to take off the whole exhaust line I guess. I am still trying to remove that one

Try to remove positive baterry terminal for 20 minutes and install it nack. That will reset your ECU and it will run little rought tilll learn new change in 02 sensor.

They are not noted for fuel mileage. You can change the O2 sensor, but this is not the problem.

this is a lean code bank one the o2 is not the problem it is working because it gave lean code a o2 code would be136 or 138 depending on which one .i would suspect vacuum leak in pcv hose assembly .this a common problem.if you still want to change 02 it will be passenger side upstream 02 which just below exhaust manifold.171 says lean bank one and bank one is the side were #1 cylinder is pass side. i hope this helps and please rate my answer thanks.

An O2 sensor will not cause a miss, period. I would think the problem may lie with the #3 coil, or the wiring to it. What are the trouble code(s), give me those and I can be more helpful

There are four o2 sensors on this truck. one on each side just below the exhaust manifold, and one on each side behind the second catalytic converters. (just about even with the back of the front doors.