Cold Startup Problem (First time)

[brtnstrns]

This morning I started up my car after it sitting overnight and when I started it up the RPMs dropped down below 500 or so and then it stalled out immediately. The car would not stay on unless I held the throttle down. This is the first time this has happened since I've had the car (about 1 month) and it wasn't particularly cold outside this morning, probably around 68 or 70 degrees. Well I drove the car about 3 miles back to my apartment (it was in a garage that it could get towed in) by braking with my left foot and holding the throttle at 1000 RPMs at stop lights so that it wouldn't stall out. By the time I got back to my apartment, about a ten minute drive, the car was fine: I let my foot off the gas and it stayed idling like normal. This obviously isn't a huge issue since the car stayed on after being warmed up a few minutes but what could I look at to ensure the car won't have any cold-start problems in the future?

 

[wmburns]

Possible IAC problem.

Basically the same problem as GDawg (same diagnostic procedures).

http://www.stangnet.com/mustang-forums/800824-high-idle-anyone-wmburns.html

Do you have a ODB2 scanner to monitor the IAC percent? Turn the AC on/off and verify that the percent changes.

Consider cleaning the IAC (although it may only be a temparary fix). Clean the MAF.

Note, my 2000 manual will sometimes dies when cold. Usually happens when coasting to a stop immediatly after pulling out of a parking space. It does it infrequently so I just ignore it.

 

[brtnstrns]

Possible IAC problem.

Basically the same problem as GDawg (same diagnostic procedures).

http://www.stangnet.com/mustang-forums/800824-high-idle-anyone-wmburns.html

Do you have a ODB2 scanner to monitor the IAC percent? Turn the AC on/off and verify that the percent changes.

Consider cleaning the IAC (although it may only be a temperary fix).

Sorry I don't know what the IAC is. That thread seems to be about high idling problems whereas mine was just temporarily stalling out at idle. There was no jump in RPMs or anything, it was just that I would turn it on and if I didn't press the gas down it turned itself off. Then 10 minutes later it was fine.

 

[wmburns]

IAC= Idle Air Controller. Trouble shooting an IAC is the same (high or low idle). Except with high idle it is higher possibility of problem being a vacuum leak. With low idle it is more likely to be the IAC itself.

The IAC is on the throttle body. Follow the 1/2" line from the intake tube to the the throttle body. Some Mustangs have a square piece mid way in the bypass tube.

The PCV line goes from the right hand valve cover to the TB.

It is a long shot, but excessive EGR flow could cause idle problems. There shouldn't be any EGR flow when cold. However, one would expect it to happen more frequently than just when cold.

Consider cleaning the MAF. Use cleaner designed for the MAF.

 

[scupking]

Replace your IAC. My car did this a few years back. Replaced the IAC and it was all better.