bigred99

hey guys, i just bought a 01 gt pretty much stock just a changed exhaust and it seems when its really cold out and i go to start it the computer doesn't recognize that the motors cold and wont go to a higher idle so i have to rev it up for like three min till the motors warm, think its a temperature sensor?

Z28KLR

On a cold start, if you just leave it alone, what does it idle at? Mine cold start idles at around 11-1200 all year long (and about 750 when warm), regardless of if it's 35* or 95* outside, which I think is a pretty normal engine speed.

teej281

My high idle is set to about 1000rpm's and once its warm, it will drop to about 700-750. I forget anymore what its set at. But OP, do you have access to a code reader or a handheld tuner??? Plug that in and see if youre throwing any codes cus it might tell you right there and then what your problem is. I think if you go to autozone or advanced auto parts they'll plug your car into their code scanner to get whats going on.

Kenny_k82

My idle is goofy on my 01gt. It runs at about 1k idle all the time even when it was -15 out. It likes to drop to 750 and then jump back up to 1k randomly which seems odd. I think mustangs just idle funny at all times.

bigred99

its werid when i go to start it if its been cold it will crank but wont catch unless im on the throttle reving the r's up to about 1k, after keeping it there for like five min it will automatically stay there and then drop low to about 4-500 but when i go to keep it reved up if i don't stay on it the motor will just boug out and stall out

99BlackPonyGT

idle air control valve needs cleaned/replaced

neubstang

I had a bad IAC a few years back without throwing any codes, I agree that it would be a good idea to change out the IAC after you verify that there are no codes for something else.

Eagle2000GT

It's most likely a bad IAC. Or, since you just got the car, the previous owner could have done the IAC mod to reduce rpm hang and gotten the hole in the gasket too small. When you replace your IAC make sure you get a new gasket.

bigred99

thanks guys, where is the IAC? is it easy to replace?

Chopper

You can clean the IAC by using spray carb cleaner.Get the engine warm,then stick the little straw that's taped to the can between the hose going into the IAC and either with a helper or by using the bellcrank on the throttle blade,keep the engine running while spraying the carb cleaner into the IAC.This will clean everything downstream of the IAC including the intake valves and,to a point,the combustion chambers.
The smoke might be teriffic and you might throw a CEL but if the CEL lights,unhook the battery for a few minutes and reconnect.
You might need to stick a small nail in beside the straw,they aren't as strong as they used to be and the hose might crush it closed.