Cold Starting Problem

[Jackel402]

My Marauder has recently been having trouble starting in the cold. When I go to start it, it revs up but when it comes back down to were it should be catching the idle it drops below were it should be and dies. I have to hold my foot on the gas at were the cold idle should be for a few minutes and gentle let my foot off until it catches. But when it does catch its only sitting at about 300-400rpm. Once it finally warms up it idles at 600. I tried replacing the IAC valve and the throttle position sensor but neither seemed to do any good. Does anyone have any idea what it could be. :(

[Jackel402]

Sorry forgot to mention that it appears that the previous owner installed a BBK Power-Plus 65MM Throttle Body and it looks like they also did a K&N Intake on it as well. I don't know if either one of these could affect it but it doesn't hurt to know.

[omarauder]

Check the Mass Air Flow sensor, could be dirty, wiring problem, U/S. Do you get any codes ?

[Stranger in the Black Sedan]

I'm out of my league w/ the Ford engine management but with a throttle body and EFI you have a minimum air setting. The IAC can only trim idle speed so much w/ its metered vac. leak. If the minimum air setting, which is mechanically established by the position of the throttle body blade(s) at idle, usually using an adjustable stop screw, is way off, the IAC won't have enough compensation to trim the idle into range. If the throttle blades are too far closed, the IAC wide open may not be enough to get the correct idle speed w/ a cold engine. Is there a screw on your throttle body? Try opening it just a hair a little at a time and see if you can get the speed to come into range, without throwing a check engine light for idle speed high.

[Thunderace]

our gmarq does this once in awhile also,sometimes you have to hold your foot on the gas to keep it running,then theres a click sound and it idles up fine.it only does it when its cold,i thought i read a thread on this before a while back

[musclemerc]

mass air meter!

[Aren Jay]

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