4kq runs rough when cold

Huw Powell audi at mediaone.net
Sun Nov 26 23:32:23 EST 2000

most likely the temp switch on the underside of the top coolant hose -
tells the ecu engine temp so it can compensate for cold conditions with
more air and fuel.  I forget what its resistance values are suppsoed to
be cold/hot right now but I'm sure someone else could find it in their

> 1986 4000 S quattro, 5 cyl, non turbo,
> 1.Starts fine, hot or cold, cranks and fires rigth away
> 2.After running a few seconds it will start to miss (idle)
> 3.After running a couple minutes it will stall (idle)
> 4.If I try to drive it will buck and miss and be a really difficult to get up
> to highway speed
> 5.After running 15 minutes it will run like a champ, then once in a while miss
> fire
> I have unplugged various sensors and switches but cannot fool it. It will
> however run quite well when the full throttle shut is making contact (running
> rich). 

Huw Powell



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