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Chris (aka- Moose)
Chris (aka- Moose), Technician
Category: Ford
Satisfied Customers: 48381
Experience:  16 years experience
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2005 Freestar: a misfire on cylinder 1 and replaced the coil pack..van

Resolved Question:

2005 Freestar LTD 4.2 152k miles
In October had a misfire on cylinder 1 and replaced the coil pack and cleared codes.

Yesterday the van exhibited the same problem, driving in the rain began a bad misfire and loss of power. Limped off the highway, checked codes with scanner and showed misfire on cylinders 3-4 and Primary Coil failure code. Assumed coil bad again. Vehicle would idle but misfire badly under load. Towed to shop (not dealer), they checked codes to verify and they replaced coil pack. Small improvement, but still misfired but no codes displayed. Replaced plugs and wires. They were replaced at 110k miles with OEM parts. The van still misfires and has an intermittent sound that sound like a backfire. Also a knocking type sound at the misfire, but it is not a regular interval misfire / knock. Did compression check and was within normal on all cylinders.

Could this be a PCM problem? Shop said it needed to be towed to dealer for this replacement, but don't want to gamble on $600 to $700 repair that may not be the problem. This shop mgr was a 20 year Ford dealer tech / svc manager and said he is stumped. There is a TSB for the PCM getting wet, but this van showed no sign of water intrusion into the PCM, but it was evident near the 120 pin plug.

Found one vacuum line that was cracked and replaced. The van actually ran better with the vacuum leak.

The van is 180 miles from home and I've already spent $600 on these repairs and a rental car to get home. Going next week with trailer to pick it up.

Any thoughts would be appreciated.
Submitted: 5 years ago.
Category: Ford
Expert:  Chris (aka- Moose) replied 5 years ago.

Hello, I'm Chris.
I will do my best to answer your question fast and accurate using the info you have provided. Thanks for visiting Just Answer.


You need to get a scan tool on it which can monitor the PCMs ground signals to the coil to see if any are dropping out which would mean the PCM has driver faults. You also need to monitor the cam and crank sensors since they tell the PCM when to fire the fuel injectors and the spark plugs. I would really be checking the cam sensor and synchronizer since there a common failure at this mileage with these codes.

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