Another idle problem question with a twist..

So it doesn't perform well in open loop. It could be many things, but most likley your problem will have to do with fuel delivery. Crank the car, when it starts to do this, shut down and check a plug. If the plug is wet, or a lot of black then you are probally running rich, if "clean" or white, your probally running lean. What calibration is the MAF and what injectors? The oxygen sensors will for the most part correct, but when the motor is cold, they arn't working yet.

And he should be able to pull codes. See JRichker's post about doing so.

Did anyone check the ECT (I have no idea what was referred to in the opening post)?

Good luck.

Help in the pulling codes department...

Dump the codes and see what the computer says is wrong…Codes may be present in the computer even if the Check Engine light isn’t on.

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.

See http://www.troublecodes.net/Ford/
OR
See http://www.mustangworks.com/articles/electronics/eec-iv_codes.html

IF your car is an 86-88 stang, you'll have to use the test lamp or voltmeter method. There is no functional check engine light on the 86-88'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 Wal-Mart.

Or for a nicer scanner see http://www.midwayautosupply.com/detailedproductdescription.asp?3829 – It has a 3 digit LCD display so that you don’t have to count flashes or beeps.. Cost is $35.

Wal-Mart may now have the LCD display scanner for less than $35

I had the exact same problem as you after my Mass air conversion. I raised the idle speed up a bit (to about 850-900 RPM) and advanced the timing a bit. After that, it ran like a champ.

EDIT: There were no faults stored in my case.

I agree, get the codes first.