Dont know if this is your problem, but it's an easy fix, and a known problem. This is a Ford Tech Bulliten on the intake manifold runner control, have a look:
SPARK KNOCK UNDER LIGHT LOAD AND ACCELERATION - 3.8L, 3.9L, AND 4.2L - SPLIT PORT INTAKE MANIFOLD RUNNER CONTROL (IMRC) TECHNICAL SERVICE BULLETIN Reference Number(s): 07-16-17, Date of Issue: August 20, 2007 Related Ref Number(s): 07-16-17 ARTICLE BEGINNING ISSUE Various vehicles equipped with a 3.8L, 3.9L or 4.2L engine and Split Port IMRC may exhibit spark knock under light load and acceleration. ACTION Follow the Service Procedure steps to correct the condition. SERVICE PROCEDURE Inspect for disconnected IMRC actuator rods. 1. Check both right hand and left hand side IMRC rods are properly attached to the actuator motor and intake manifold runner. 2. If the IMRC actuator rods are found to be connected properly, do not continue with this TSB. Refer to Powertrain Control/Emission Diagnosis Manual. 3. If any IMRC actuator rods are disconnected, refer to Workshop Manual (WSM), Section 303- 14 for IMRC service. 4. If any IMRC actuator rod linkages are found disconnected, replace all four (4) linkage rod retainers. ( Fig. 1 ) Fig. 1: Lower Intake IMRC Linkage PARTS INFORMATION PARTS INFORMATION
FORD: 2001-2004 Mustang; 1996-2003 Windstar; 1997-2003 E-150; 1997-2008 F-150; 2004- 2007 Freestar MERCURY: 2004-2007 Monterey
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Sunday, April 12th, 2009 AT 7:24 AM