1983 944 idle hunting????

[onthesolidrock]

over a month ago i had the hose from the radiator to my water pump blow a hole, or rather, like an idiot i put it back in after a radiator replacement and put it too close to the fan and it wore a hole. Anyway, when that happened it over heated, got a new hose, topped off the water and realized my oil cooler seals had failed. so i went through everything to replace the seals. the day i got it all put back together i jumped in and took it for a ride, i let it warm up first and about a half mile from my house i stopped at a stop sign and it about stalled on me, clutch was all the way in so it wasnt me, and the idle dropped to 300 RPM, and back up to 800 and right back down again. did that a couple times then cleared up, so i took off and the car runs great, but continued to idle funny at stop signs, any throttle position besides closed and the engine runs like a top. 75 MPH and not a problem same at 15 MPH. the car does not hunt when its cold, in fact it takes about 15 minutes of it running before it starts to idle funny. and before it overheated the car idled right at 900 RPM when cold and 1,000 RPM when warm, now it idles between 1,100 and 1,200 RPM, the hunting isnt always there, it comes and goes, sometimes tapping the gas pedal while at idle will cause it to hunt, sometimes not, sometimes tapping the gas pedal when it is hunting causes it to stop, but not always...

i read that it could be a bad o2 sensor and that unplugging it would cause the car to run in 'open loop' mode???... and would clear up the hunting idle... so just now i started the car, it was hunting and i unplugged the sensor and nothing changed. plugged it back in and still no change... any ideas? trouble shooting those ideas? i have inspected all the vacuum hoses and i cant find any leaks or cracks. and i have replaced both the speed and reference sensors 6 months ago along with a typical tune up fuel and air filters, plugs, rotor and cap and coil.

another little tid bit i just remembered, in light of all the problems im having with the idle, it only idles funny when not in gear or with the clutch pushed in. i can put it in first and let the clutch out without having to touch the gas and the engine doesnt idle funny at all, it stays at 1,100 RPM while i slowly let the clutch out and once the clutch is fully released it stays at 1,100 RPM without a problem. it only idles funny when out of gear or with the clutch pushed in.

[Bradical]

The issue could be the idle control valve, which is located under the intake. More likely, however, the issue could be caused by a bad or failing dme coolant temperature sensor, which is located on the drivers side of the radiator. It probably bit the dust in the process of all the cooling issues

[sausagehacker]

+1 on the DME temp sensor. it's likely that it was affected by the overheating, and is now telling the DME to send less fuel at warm temp, causing a lean condition. When the idle hunts, it's generally a lean condition.

Re: the idle valve (on an early car). when the car is fully warmed up, that valve is completely closed anyway so it's unlikely to cause a hunt. If it were stuck open you would have an abnormally high idle.

[mattdavis11]

Intake boot and the afm. You might have an umetered air leak.

[onthesolidrock]

just ordered a DME Temp Sensor.... hopefully thats the problem. on a slightly unrelated subject, a few months back i ordered the wrong part for my car, i wanted a fan switch but ordered a water temp sensor instead.... i havent replaced it yet because i cant find where it goes. my fan switch has 2 pins on it and screws into my radiator on the driver side, i already replaced that, but where does the sensor for the water temp go? its for the gauge not the DME.