2003 4.0 SOHC misfire cyls 1, 2, & 3

[Wolfrom64]

I,m working on a friends 2003 Explorer Xlt has a 4.0 sohc flex fuel, we have tried new plugs, wires, a known good coil pack. Fuel pressure is 65 psi. scanner gives us a misfire on cyls 1, 2, & 3, rich bank 1 and lean bank 2. don't have the codes with me but can get them tomorrow. any help would be appreciated. Thanks

 

[Wolfrom64]

Sorry wrong sub forum please move.

 

[2000StreetRod]

rich on 1 lean on 2

Excessive rich on one bank and excessive lean on the other bank is frequently due to cross connected pre-cat O2 sensors. Many owners mistakenly think that bank 1 is the driver side. Bank 1 is always the bank containing cylinder 1 which is the passenger side (in U.S), front cylinder for the SOHC V6. An easy test is to disconnect one of the O2 sensors (driver side is easiest for 2nd gen, I don't know about 3rd gen) and see if the PCM reports an O2 heater failure for the wrong bank.

 

[Wolfrom64]

Thanks for the info, will give it a try this weekend.

The shop he had do work on this thing is not known for being reliable.