Check engine light on, oxygen sensor washing out cylinders?

BOB FELTON

MEMBER
1996 FORD BRONCO
5.0L
V8
4WD
AUTOMATIC
159,000 MILES

Check eng light oxygen sensor washing out cylinders 3, 4, 7, 8.

Wednesday, November 16th, 2022 AT 1:57 PM

4 Replies

JACOBANDNICKOLAS

MECHANIC
109,896 POSTS

Bob,

What code or codes are you getting? By washing out, do you mean its flooding? Please explain.

Let me know the codes and exactly what is happening so I can better help you. Also, if you have a live data scan tool, let me know what the short-term fuel trims are and what the coolant temperature sensor indicates when cold.

Take care,

Joe

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Wednesday, November 16th, 2022 AT 8:54 PM

BOB FELTON

MEMBER
3 POSTS

Lean on one rich on the other.

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Thursday, November 17th, 2022 AT 3:55 PM

BOB FELTON

MEMBER
3 POSTS

Lean and rich codes o2 sensor, replaced several parts.
Started knock in engine, replaced engine, checked, blocked fuel filter, blocked cat. Checked codes had a bunch replaced comp helped some, checked codes rich and lean, replaced, distributor, plugs wires, MAP, mas EGR, coolant temperature bypass valve, and fuel pump. It runs good cold warms up light comes on runs rough.

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Thursday, November 17th, 2022 AT 4:08 PM

JACOBANDNICKOLAS

MECHANIC
109,896 POSTS

Hi,

Do you have an exhaust leak on one side of the engine (exhaust manifold) before the catalytic converter? That can cause a lean mixture on one side. See pic below for sensor locations.

Joe

See pic.

Image (Click to make bigger)