Why Does It Missfire! - Page 2
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This is a discussion on Why Does It Missfire! within the General Maintenance, Troubleshooting & Accidents. forums, part of the Tech & Modifying & General Repairs category; Originally Posted by mycologist I did a lot of searching and got some good advice when I had audible ping ...

  1. #16
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    Quote Originally Posted by mycologist View Post
    I did a lot of searching and got some good advice when I had audible ping not too long ago. Here is a list of possibilities pasted from my thread. Engine managment would be a very good consideration for you and you could do some logs, they might help.

    Results from searches:

    1)Cobb map is conservative, runs rich. Should be trusted.
    or (take your pick on the thread)
    Cobb map is actually leaner than stock - never heard of anyone running Cali 91 map on 93 octane, but is a possibility.



    2) PCV valve - should be changed every 15K miles, or never (take your pick). Mine was fine.

    2.a) Oil catch can - not done.

    3) Turbo oil seals shot - seems not. No oil in downpipe, not much in intercooler

    4) Engine deposits - can cause preignition as well, or increase compression and otherwise cause spark knock (at issue here). Finishing 1st tank with synpower cleaner.

    5) Spark plugs - do show signs of detonation (metal balls stuck to ceter electrode). Plugs replaced with OEM gapped to .028 (yesterday, not tested hard yet).

    6) Blow by - oil in intake, reduces octane. Check compression.

    7) Elevation - Colorado people say 91 octane = 93 octane there, should be a safeguard
    or
    Need higher octane at high elevation (web auto professionals and occasional threads)

    8) Boost - peaks at 15.8 settles at 15 then tapers. Compensation map in ECU reduces peak boost by 1 PSI per ~3500' IIRC, so normal stage II numbers.

    9) Vacuum issues (haven't figured out how to check system yet).

    10) Injectors plugged, tired, or imbalanced (40K miles, always top tier gas, never cleaned). Unlikely - all four cylinders are affected.

    11) MAF or Temp sensor problem.

    12) Dealer - go parade my just installed stage II setup and void my warranty on a totally unabused motor with a potentially bad ring land. Get unheard of and unreported "ping" reflash that was never mentioned when I was there complaining about ping.

    13) Knock Sensor? Don't know how to test that.

    14) Head gasket??? I guess I should add this because I have had to burp the coolant a few times recently. I had a small coolant leak from a line a while back but it was supposedly corrected/pressure tested at the dealer. The system was then flushed at 30K (dealer) and there has never been any indication of overheating.

    i think getting this re-flash may help...but i'll def go down your list tomorrow when i have the car apart.

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  3. #17
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    Holy hell thats one narly check list. Data loging would be very usfull in this situation. Go buy a tatrix cable.

  4. #18
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    Quote Originally Posted by 06lack View Post
    i think getting this re-flash may help...but i'll def go down your list tomorrow when i have the car apart.
    Oh, I should have taken that out - mine is an '03. I haven't heard of a dealer reflash for an 06. That you can do with the cable mentioned above anda have a good stage II map to match your modifications. It will help your reliability and power.
    "From a little spark may burst a mighty flame." - Dante
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  5. #19
    Admiral Ackbar the 1st mycologist's Avatar
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    Oh, except search for tactrix, not tatrix (he made a typo)
    "From a little spark may burst a mighty flame." - Dante
    "The stitch is lost unless the thread is knotted." - Italian proverb

  6. #20
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    figured it out tongiht after my hockey game.

    P0340 and P0345

    both are cam position sensor related....how hard are these ****s to swap?

    I insist on doing all my own work.

  7. #21
    He simply abides. SD_GR's Avatar
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    http://forums.nasioc.com/forums/show...hreadid=511538
    and
    http://forums.nasioc.com/forums/show...ght=cam+sensor
    and for more info
    http://forums.nasioc.com/forums/sear...rchid=10764528

    The sensor is located on top of the head on the US driver's side (left hand side when seated in the cabin and looking toward the front of the car).
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  8. #22
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    Quote Originally Posted by 06lack View Post
    the cars got an twin plate excedy carbon-carbon clutch with there lightweight flyweel, its NEVER acted like this before.

    as for the timing belt i have no idea how to check for that issue.

    it seems to me that if the engines timing was off it would act weird all all ECT's
    you would have a cam position sensor code if the belt was off..your likely cause is your a/f sensor..there is a tsb on them and also a reflash...also there is a union screw filter that causes that same issue...
    New England F4

    feel free to pm me with any questions..

  9. #23
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    Quote Originally Posted by 06lack View Post
    then why is this only happening now? (after 35k)

    and why no engine lean code?

    (dont think i'm being a ****, just asking a question)
    has he had the mods on for 35k?
    "Whatever it takes"

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