TSB 05-26-3

FORD: 2004-2006 Ranger

ISSUE

Some 2004-2006 Rangers 3.0L-2V "Vulcan" vehicles may exhibit:

- Malfunction indicator lamp (MIL) on with diagnostic trouble codes (DTCs) P0300-P0306 and P0316

- Rough running at various RPM

- Rough idle

- Misfire

ACTION

This may be due to an engine exhaust valve seat recession causing a loss of compression. Refer to the following Service Procedure to diagnose exhaust valve seat recession.

SERVICE PROCEDURE

1. Perform a power balance rest to clarify if a cylinder is misfiring. Identify and keep record of any cylinder that has a concern.

2. Perform a manual compression test with the spark plugs removed to locate any cylinder that may have low compression. Refer to the appropriate Workshop Manual, Engine System, General Information, 303-00.

3. If no low compression is found per shop manual instructions, proceed with normal misfire diagnostics per the Powertrain Controls/Emissions Diagnosis (PC/ED) Manual for the appropriate model year.

4. If low compression is found and it is a cylinder that had a misfire on power balance, perform a leakdown test to determine the source of leakage that may be causing the low compression. Refer to the appropriate Workshop Manual, Engine System, General Information, 303-00.

5. If low compression is found in a cylinder that did not have a misfire detected then proceed with normal base engine diagnostics per the Workshop Manual, Engine System, General Information, 303-00.6.

If the exhaust valve is identified as the source, replace both cylinder heads with the newly released service cylinder heads. Refer to the appropriate Workshop Manual, Section 301-01A.

PART NUMBER / PART NAME

6U7Z-6049-A / Cylinder Head Assembly

2F1Z-6079-BB / Upper Gasket Kit

F8 DZ-6065-AA / Cylinder Head Bolts

F7DZ-9448-BB / Engine Exhaust Gasket

4F1Z-658-AA / Valve Cover Gasket

F6DZ-9439-C / Side Gasket

F2DZ-9A425-AA / China Gasket (Front)

F3DZ-9A424-BA / China Gasket (Rear)

4L5Z-9H486-AA / Gasket-Upper Intake Manifold