[s-cars] Rough Idle on startup, Rich exhaust, warms up and fine...

[Ian Duff]

Sounds more like an ignition problem, one coil not firing until warm.  
Try the old "unplug one injector at a time, if the idle roughness  
gets worse, that coil is ok, if the idle roughness stays the same,  
that coil is bad" trick to see. If that's it, it's a different  
solution than replacing some sort of temp switch, plus it's an easy/ 
cheap test of a known culprit of a rough idle. HTH.
-Ian Duff.

On 27 Jun, 2007, at 09:19, Nic Bode wrote:

> Gentleman,
>
>
>
> 93 S4 with 109K on the clock. Start up on cold, either overnight or  
> after a
> day of sitting the parking garage at work. Runs rough like on 4 cyl  
> and
> strong unburnt fuel smell from exhaust. Let it idle like that for 5  
> minutes
> maybe and something changes and it idles fine, runs fine. My  
> thoughts are
> obviously it is temp related but what? Coolant? Oil? I really think  
> coolant
> related but I don't know of a sensor that would read either coolant  
> or oil
> temp and feed that info to the ECU to tell it to run rough like  
> that when
> cold. Am I looking at another Multi Function Coolant Temp switch  
> under the
> intake replacement?
>
> Just want to narrow down my buy a switch and replace repair bill. I  
> know I
> could run all kinds of temp and ohm readings from various spots but  
> really
> don't have that kind of time or money for the indy to spend that  
> time under
> the hood with all the probes.
>
>
>
> Thanks
>
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