Whenever I start my car after it's been sitting for over about 8 hours or so (overnight), it will crank and start up fine... but then the rpms drop and it stalls. It's done this for awhile, just tuned it up about 1,000 miles ago with new plugs, wires, cap, and rotor. What could be causing it to want to stall when it's cold like that? It runs very poorly until it's up to normal driving temps.
The IAC (or IAB) s the cylinder mounted on the side of the Throttle Body. Get some TB cleaner and clean the TB. Remove the IAC and clean it too. Clean the electrical contacts for the IAC while you are at it.
MIne suffered the same problem and the above cleaning process, especially scraping & cleaning the electrical contacts fixed it.
if the iac cleaning fails, you might check the ECT and ACT sensors - if one or the other is out of calibration, that can lead to stalling out when cold.
Prior to doing anything with the ECT or ACT, dump the codes and see what the computer says is wrong…
Here's the link to dump the computer codes with only a jumper wire or paper clip and the check engine light, or test light or voltmeter. I’ve used it for years, and it works great.
IF your car is an 88 stang, you'll have to use the test lamp or voltmeter method. There is no functional check engine light on the 88's except possibly the Cali Mass Air cars.
Codes have different answers if the engine is running from the answers that it has when the engine isn't running. It helps a lot to know if you had the engine running when you ran the test.
Trouble codes are either 2 digit or 3 digit, there are no cars that use both 2 digit codes and 3 digit codes.
For those who are intimidated by all the wires & connections, see http://www.actron.com/product_detail.php?pid=16153 for what a typical hand scanner looks like. Normal retail price is about $30 or so at AutoZone or Walmart .
Look for codes 21 or 24 whwn you do the scan. They are for the ECT & ACTsensors.