I am new to the forum and looking for some assistance. Here is the background:2006 4.0, Automatic, 4x4, 101,000 miles.
Check engine light is on and steady, however for short periods (1-2 minutes) it will flash, along with low/rough idle, and then resume to steady.

I have replaced, plugs, wires, coil pack and MAF to no avail.

Code reader says bank 1 is lean and bank 2 is rich. Also has indicated cylinder 1 misfire. Thinking of changing O2 sensors, however I have a feeling they are not the cause.

Any ideas are greatly appreciated.

 

Looks for exhaust leaks, any intake leaks. A flashing light it a missfire

Either way a lean code means air is getting in somewhere between the MAF and the primary O2 sensor.

A leak on an exhaust manifold can cause a missfire on a cylinder

 

Flashing CEL means "CHECK ME NOW!"

Yes, I would agree O2's sensors read like they are working.

Does your reader have live data ability?
You should see O2 data changing meaning they are working OK
You can also see the 3rd O2 sensor data, bank 1 sensor 2, see what voltage it shows.

What did cylinder #1's spark plug look like?

The 4.0l sohc has a PCV valve hose that often cracks at the elbow, cause a hard to find vacuum leak.
Have a look here, pictures too:
https://www.ranger-forums.com/4-0l-o...mon-cel-93776/

 

Flashing CEL means "CHECK ME NOW!"

Yes, I would agree O2's sensors read like they are working.

Does your reader have live data ability?
You should see O2 data changing meaning they are working OK
You can also see the 3rd O2 sensor data, bank 1 sensor 2, see what voltage it shows.

What did cylinder #1's spark plug look like?

The 4.0l sohc has a PCV valve hose that often cracks at the elbow, cause a hard to find vacuum leak.
Have a look here, pictures too:
https://www.ranger-forums.com/4-0l-o...mon-cel-93776/