Low idle at start

[exitwound]

I've been researching this problem (at least I think it's a problem) for months without coming to any conclusion.

When the engine is cold (doesn't matter what the ambient temperature outside is, 20F or 60F), the car will idle at 400-600rpm and near sputter out, but it's a steady idle, no fluctuations. After the engine runs for a minute or two, the engine begins to level out and idle higher. When the engine is warm, the idle is >1000 and very steady.

I have replaced all the vacuum lines in the car as well as the DME Temperature sensor, the Oxygen sensor. I have adjusted the TPS to proper adjustments. All new hoses all around, including the small ones by the ICV.

At this point, I have the idle set to >1000 because if I set it to the 850-950 as recommended, the car idles when cold at 300-500rpm and WILL stall out.

Any ideas? How does the ICV fit into the idle? I can't seem to find much reading material as to how it actually works.

[exitwound]

Took the intake off and worked on the ICV. I applied a 9v current to it, and it shuts promptly and easily, meaning it's working correctly, I'm guessing. All of the hoses were snug, and there's no punctures or leaks as far as I can see. I readjusted the TPS as well, not that it needed it. But I made sure it was all working properly.

[minton2001]

Common problem. Subscribing.

[nightheart]

Originally Posted by minton2001

Common problem. Subscribing.

Me too. Mine does the same thing, and I replaced most of the same things. No ideas, just hoping someone else has an answer.

[strikinglight]

Same thing here too. Mine also has a weird thing where it will crank over without starting then as soon as I turn the key off and on again it fires right up... To a low idle sometimes. Not sure if the two have anything to do with each other...

[SuperXRAY]

Though ours is an early 944, I cleaned and repaired the AFM, especially the idle bypass port. Also cleaned the idle bypass on the throttle body (AAV). Couldn't tell you which one did the most good, as I did them both before putting things back together. Problem is gone, though.