I have a 2004 Freestar SES with the 3.9 with 140,000 ish miles on it. Do these engines have some sort of spark knock censor on them, if so where is it located at? When pulling out but not always there is like a spark knock on the drivers side or sounds like coming from that side. When the vehicle accelerates the knock stops. Not time for a complete tune up, but not had time to pull spark plugs out and look yet.

 

For the front head assembly, the knock sensor should be screwed into the driver's side of the head on the lower left corner (only thing screwed into the side of the head). With all things being equal, that would put the rear head assembly's sensor on the passenger side, unless Ford put holes on each side of the head. If that's the case, then the rear head knock sensor may also be on the driver's side of the rear head assembly.

 

TSB 07-16-17 says to check the intake manifold runner control (IMRC) actuator rods, and make sure they're connected. Apparently the clips broke sometimes, causing spark knock under light acceleration.

I tried to attach a picture form the bulletin.

 

If you need to order the parts from that TSB the part numbers are WHITE: F5RZ-9F955-AB (#F5RZ9F955AB: BUSH) and RED: 6F2Z-9F955-A (#6F2Z9F955A: BUSH (Pack of 2)).

 

Thanks lake for the information sharing with us.

 

You can get 2 for $8 (Motorcraft), or you can get the DORMAN branded (white) set of 5 for about $5 like I did for my Freestar. I didn't need them, but replaced them due to age. Mine just fell apart when I replaced them. Better in the driveway, then one the road. Set of 5 comes in handy, especially when you drop one and it does the vanishing trick (been there, done that). My local Autozone had them in stock.

Dorman/Intake Manifold Vacuum Retain Bshng 47099 - Read Reviews on Dorman #47099

 

Thanks for the info.