[s-cars] Mystery Miss

[Jerry Scott]

I had the same problem a while back and tried everything but change the 
coil on the msifiring cylinder.  When I made that change the problem 
went away.  There were no external signs that the coil was failing 
intermittently.
Jerry

Bob Rossato wrote:

>Bob,
>
>I have developed the same exact misfire.  I first noticed it about a month
>and 1/2 ago when I came back from a business trip.  The car had sat for a
>week and when I first started it up upon my return it ran rough.  Sounded
>like it was on 4 cylinders.  Revved it up and it continued misfiring, but
>after a minute or so it smoothed out.  No problems while driving.  Strong as
>bull.
>
>Two or three weeks later it happened again after having sat unused for 4-5
>days.  Same situation.  Clears up after a minute, then no more problems.  If
>I drive it daily it never gives me a problem.  Let it sit for 4-5 days and
>it will misfire at start up.
>
>This past Sat morning I tried to isolate it by pulling injectors but it
>cleared up by the time I was able to go through all five injectors.  I did
>pull codes after that and got a "Fuel Injector for Cylinder 2 - Open or
>Short to Ground - Intermittent" error code.  I assumed it was because I
>pulled the injectors while it was running, but because I only got it for
>cylinder 2 instead of all 5 (or at least more than 1) I thought this was a
>possible lead.  Reset codes.
>
>Fast forward to today and your post prompted me to go try it again as I
>hadn't driven the car all week.  This time I set up VAG-COM prior to
>starting it so that I could see if it would throw the injector code again
>when I started it.  It ran rough again as expected, but alas, no codes other
>than the CPS code, which was expected as I was checking codes prior to
>starting the engine.
>
>I was talking to Tom Mullane about it Saturday.  One theory he had was a
>fuel pressure/vapor lock possibility that takes a while to clear up, but we
>were a bit perplexed by why it would occur on a middle cylinder rather than
>an end one.  But based on tonight's trial the Cyl # 2 code may have been a
>red herring.
>
>Anyway, no answers for ya other than to say "me too".  Maybe it's a Bob
>thing.  I'm going to let it sit for a while again and see if I can isolate
>the cylinder at least.
>
>If you figure it out let me know.
>
>Oh, for what it's worth, my car has 77k miles on it, plugs have about 40k on
>them, and the plugs and boots looked good with the exception that the boot
>on # 5 had the end lip torn off.  No oil in the spark plug wells.
>
>Bob
>
>  
>
>>-----Original Message-----
>>From: s-car-list-bounces at audifans.com
>>[mailto:s-car-list-bounces at audifans.com]On Behalf Of Robert Myers
>>Sent: Wednesday, September 29, 2004 9:34 PM
>>To: s-car-list at audifans.com
>>Subject: [s-cars] Mystery Miss
>>
>>
>>
>>Hi Y'all,
>>
>>Thanks to all who responded about my son's dealings with his
>>Mercyless Benz
>>stealer.  Apparently contacting the corporate offices helped.  He finally
>>has his car back from the stealer.  Now on to the topic of this post.
>>
>>My '95 urS6 (RS2ed) has developed a mystery miss.
>>
>>It happens only when the engine is stone cold.  It disappears after the
>>engine has run for less than two minutes and does not come back until the
>>next time the engine is stone cold.
>>
>>FWIW, I have localized the miss to cylinder #4.
>>
>>I have pretty much ruled out a fault with the PSO since the miss
>>disappears
>>after the engine has warmed up a bit.
>>
>>I don't think it is a problem with a weak coil because there is
>>absolutely
>>no miss at high boost which is when a weak coil would show up.
>>
>>I put new plugs in about a week ago so that shouldn't be the
>>problem.  Performance is superb after the engine warms up.
>>
>>Plug boots are reasonably fresh.
>>
>>The wires to/from the coils have been freshly reinsulated with shrink
>>wrap.  I am pretty confident that I did this job correctly.
>>
>>What in the name of the Audi gods remains?  Any ideas?
>>
>>
>>Bob
>>Random Bushism: "A tax cut is really one of the anecdotes to
>>coming out of
>>an economic illness." George W. Bush, on The Edge With Paula Zahn, Sept.
>>18, 2000
>>_____
>>Robert Myers   304-574-2372
>>Fayetteville, WV
>>'95 urS6  Cashmere Grey
>>_____
>>
>>    
>>
>
>
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