1999-04 Mustang V8 4l Misfiring, Replace Heads Or Not?

Discussion in '1996 - 2004 SN95 Mustang -General/Talk-' started by Prototype, Dec 3, 2013.


Which 99 stang heads are better than stock ones and why?

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  1. Hello, people, i Just Joined this Community tonigh 12/03/2013 at 7:40Pm

    My problem:
    I have a (1999 Stang, V8) (after 3 years with no problems)Stock heads where messed up by Cyl#3 .. I REPLACED heads for semi-new(1,200$ 1 year ago) Before putting heads back, Mechanic ADDED some special HELICOILS that where installed before final installation so that it will have more thread and it will avoid getting another spark plug blown. After installation (1 year later 10/12/2013 ) Cyl# 5 decided to break, I sent it to the shop for Helicoil job... -_-, Today 12/3/2013 Cyl#3 is misfiring, i turn the car on, and i can feel the low compression, i use my OBD2 machine and Cyl#3 is back again after so long..

    My Questions:

    Can i add cobra heads to my 99 stang?

    Where can i get an upgrade for this FORD HEADS Typical problem?

    I live in CA Inland Empire Close to L.A...

    Any advise or comment is welcome, negative feedback, just leave it for later.. THANKS in advance

    Attached Files:

  2. I think 03-04 gt heads have more threads for the spark plugs. If it's not that bad I think you can fix it yourself, here are some basic how to and the tools to get it done. http://www.timesert.com/html/ford_sparkplug_faq.html
    Are you sure it's a stripped spark plug hole? If you are gonna replace heads maybe it's tone to upgrade and get tfs heads or do a 4v swap.
    Prototype likes this.
  3. :(i was looking into that, but would it work in a head that was already using a helicoil.. is it possible to reuse the same hole after being use with a helicoil...
  4. i will, check the sparkplug tomorrow, and if its loose ill tight it up, but if its stripped a little, i guess its done,:scratch:
  5. You know the helicoil thing I'm not sure about :/. I've never had a helicoil fail but then again I've never put one in a head. This just may be the perfect excuse to go 4v ;)

  6. 03-04 PI heads are the same from 01-04. The 2005+ crown vic heads are what your looking for, thats when ford added more threads.
  7. +1
  8. There is your problem, you used helicoil. That is used for a cheaper fix until you get timeserts. Changing my sparkplugs my helicoil came out. A few choice words persisted.
  9. Really, the Windsor heads are the most notorious for this. I have several friends over the years that have had the same problem with theirs, two of them bought their cars with the problem and the PO was kind enough not to tell them they had been heilicoiled. I have never seen a Romeo have this issue (didn't know the 05's had updated threads, glad I read that).

    + 1 on using timesert

    This is why I when I bought my 2000 I checked each plug before I bought it and so far so good. (knock on wood)
  10. @1987stangman, Never heard of this problem with Windsor heads...
  11. If you look at the pic in his first post it's got Windsor heads.

    All I can account for is personal experiences.:)