'96 Explorer - rough idle/misfire

[Lildon21]

Hey there. I'm trying to get my explorer running good again and have been replacing a bunch of stuff. Recently bought a bluetooth OBD reader and diagnostic tool (BluDriver).

The latest issue is that it is running kinda crappy when idling sometimes and sometimes while driving also, typically at lower RPMs. I just replaced the DPFE sensor and the two hoses that connect to the EGR pipe; they had been disconnected for an unknown period of time. Still running crappy though.

My next thought was to replace the EGR valve, all 3 O2 sensors, and the MAF sensor. Then if that doesn't fix it I was thinking I could do plugs & wires again and the ignition coil. I did the plugs & wires a year or two ago.

Here's what I'm getting from the diagnostic tool:

I'm guessing the first and last O2 sensors need attention? First one shows 0 volts and the 3rd one is spiking up and down.

Any help would be greatly appreciated!

 

[410Fortune]

Your bank 2 sensor 1 is out, lack of switching
It’s not going to run well until you fix that oxygen sensor

Inspect all wiring to the sensor
Check 02 sensor fuses

Bank 2 is drivers side, b2s1 is sensor closest to engine

Likely time for a new one if wiring and fuses check out

The egr codes I would
Clear and see if they return since you installed a new dpfe and hoses

 

[Lildon21]

Your bank 2 sensor 1 is out, lack of switching
It’s not going to run well until you fix that oxygen sensor

Inspect all wiring to the sensor
Check 02 sensor fuses

Bank 2 is drivers side, b2s1 is sensor closest to engine

Likely time for a new one if wiring and fuses check out

The egr codes I would
Clear and see if they return since you installed a new dpfe and hoses

Thanks! I'll check it out.
Do you know if the bank 1 sensor 1 voltage spiking up and down is normal?

 

[96eb96]

Clean the IAC and MAF sensor.
Check for vacuum leaks.
Post long and short term fuel trim at idle AND 1500 RPM.
Leave the post cat 3rd o2 sensor alone for now.
The one with the slow response could be bad.

 

[Lildon21]

Clean the IAC and MAF sensor.
Check for vacuum leaks.
Post long and short term fuel trim at idle AND 1500 RPM.
Leave the post cat 3rd o2 sensor alone for now.
The one with the slow response could be bad.

Got it, I've got a sensor on order. I'll do those things you mentioned in the meantime and then update after installing the sensor.
Short term ranges:
Idle (left) 1500 RPM (right)

Long term fuel trim for both banks was steady at 15.6% at idle and 7.0% at 1500 RPM.

Also I cleared the codes and don't have any new EGR codes. Still getting P1151 (lack of H02S21 switch sensor indicates lean) and P0304 (cylinder 4 misfire).

 

[410Fortune]

Lack of switch usually a lazy sensor
But lean condition along with cyl 4 misfire… hmmmm
Sensor 21 is bank 2 so that is where cyl 4 exists

I would inspect the plug and wire for cyl 4 right now
If you replace that 02 sensor,’clear the codes and the misfire comes back… especially if it comes back very quickly, it maybe time for injectors.
You see a misfire code is almost always an injector when the code appears quickly.. the pcm can have a difficult time determining a misfire in the ignition (coil pack, plug and wire) because it has to use timing ti determine which cyl is misfire but when it is an injector it can pinpoint the r misfire right away.

With a misfire code first we inspect ignition
Then we check fuel pressure
Then if the code persists you may try to listen the the #4 injector see if she’s
Clicking, see if the connector is tight. If the ignition and all checks out including fuel pressure and code persists… time for intake gaskets and new injector(s) o rings and seats