Hard start, cold start problem, rough idle

Bryan Foster brfoster at gmail.com
Thu Jun 29 16:40:09 EDT 2006

Thanks Derek,
What do you think of a single isolated leaky injector?  If the car was
sitting for at least 30min it could accumulate enough leaked fuel into the
cylinder causing an overly rich mixture on startup - giving a rough idle at
startup only.  I dont know why that would last up to 10min in your car
however.  It seems to fit my problem of 30-45 sec more.


On 6/29/06, Derek Pulvino <dbpulvino at hotmail.com> wrote:
> Bryan,
> I've been having the same problem for a while, and notice it also does go
> away in the colder months...in fact now that's it's warmer again, when I
> restart my car when it's warm, and last ran within an hour to two, the car
> won't idle at all without me keeping my foot on the gas...that condition
> lasts for at least 10-minutes.  Also notice the rough running when I
> restart
> the car, lot of stumbling for a couple of minutes and the check engine
> light
> will come on, but I get no fault codes.
> Right now, my key suspect is the idle stabilizer valve, and I do recall
> that
> when I last pulled it to check, the flapper/valve seemed to
> immovable.  Was
> going to do an "output test" when I get some spare moments again.  The
> only
> thing I can think is maybe this is sticking, and causing the car to be
> overly rich on warm startup...but it doesn't answer the question as the
> why
> the car wouldn't also do the same once it's warmed up.
> Some other ideas I had was maybe the temp. sensor to the ECU was crapped
> out, but resistance at the sensor was within spec when I checked, or maybe
> I've got a back check valve which is letting the fuel pressure decline too
> much between starting...but then I wouldn't have idle problems for as long
> as I do.
> All in all, this is quite frustrating and not contributing to a health
> demeanor when I'm on the road.
> Derek P
> Message: 1
> Date: Wed, 28 Jun 2006 17:05:45 -0400
> From: "Bryan Foster" <brfoster at gmail.com>
> Subject: Hard start, cold start problem, rough idle
> To: 200q20v at audifans.com
> Message-ID:
>        <9be3f0980606281405v257c1184q199efc0a6c4b9464 at mail.gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> Listers,
> I have had a couple of weeks of rough idle during cold start ups.  The car
> will start easily, but then idle very roughly for 30-45sec.  After that
> time
> it runs and idles very smoothly.  If I start it up and immediately rev the
> engine to >2000rpm then it runs very smoothly, but if I was to let off the
> gas and let the engine slow down to idle then it sputters and nearly
> stalls.  When I rev it up right after start up there is a considerable
> delay btw putting my foot down and engine response as if the mixture is
> way
> off.   It seems to happen if the car has been sitting for >1 hour.  Not
> necessarily a completely cold block.  Does this point to anything in
> particular.  Leaky injector?
> Thanks in advance,
> Bryan Foster

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