When car starts, idles to almost kill...

[Cajun JungleBoy]

When I start my car in the mornings or evenings (car hasn't been ran all day) the car idles from typical 850 rpms or so, to about 100 and almost kills, then lifts up and goes down. This only happens if the car has been sitting half a day or so or longer. IE: yesterday I drove the tC to work, so when I came home, i hopped in the mustang. started it up starts fine, but when it planes out to idle it almost kills, throw it in reverse, it dredges down again. Throw it in First, dredges down until i hit the gas to start going then it goes away. Any ideas?

[PureVenom]

Driver error.

[Cajun JungleBoy]

can't be driver error if its chillin in neutral and me not in the car...

[PureVenom]

That's your error, you're not in the car.

And, when you get in the car, that's your error as well.

You're pretty much at fault either way.

[lowflyn]

What cam does your car have?

Edit, I see you have the B cam. I was thinking it was just the cam getting back into timing. Actually...I would check my timing to make sure the computer's not trying to pull timing at idle. It might be pulling/adding unnecessary timing. Start it cold one day and watch timing with a timing light, You may can find out what's going on.

Either that or your car just sucks.

[Cajun JungleBoy]

It's a mild cam, thinking something along the lines of a B303

[PureVenom]

Quote: Originally Posted by lowflyn What cam does your car have?

we don't know for sure...we can only base it on what the guy told us since he never produced the paperwork for the work. It's pretty mild though. Nothing aggressive enough to make this a normal behavior.

[Cajun JungleBoy]

Hey rob, you know the black GT we looked at, remember how it was doing that? I'm thinking it's bad tune.... lol

[PureVenom]

Your tune wouldn't have all of a sudden gone bad. The black one did it cold and warm and had a much more aggressive cam if I remember right.

It's probably your IAC or there might be a vacuum leak somewhere....or your fuel pump is being a bitch. Hard to say right now as it is only 8:15 am.

[Cajun JungleBoy]

oh i know tune didn't go bad over night, just trying to think of things. Hmmm...

[lowflyn]

Quote: Originally Posted by PureVenom Your tune wouldn't have all of a sudden gone bad. The black one did it cold and warm and had a much more aggressive cam if I remember right. It's probably your IAC or there might be a vacuum leak somewhere....or your fuel pump is being a bitch. Hard to say right now as it is only 8:15 am.

Hell it's late man. In another 20 minutes my day gets easy.

[SpectorV]

getting 5.0's to idle right with a cam is not fun or easy~ ask bbunt302 he knows.... pm him if he doesnt reply soon and ask him about it.

[Cajun JungleBoy]

yea i may send him a pm

[SimplyOrange]

try fixing your fuel problem first since it is already tuned.

[1996stang]

We had a similar problem on a 03 gt. We replaced the IAC 2 times and it turned out he was messing with the screw on the bypass valve.That would be a place to check for problems.

[bbunt302]

Don't send me a PM. Try resetting your idle. Google "5.0 base idle reset".

There's a million other things you can do to try and help. Chances are, none of them will help. After trying them all in vain, go have your car tuned.

[SimplyOrange]

im guessing my post was looked over, it does not a bit of good to try to diagnose an idling problem or have the car retuned until the massive fuel leak is found, the inside of the car smells like a gas jugg when the car is running, it is very clear there is a fuel problem, i suggest fixing the known problems before looking for new ones.

as far as idling a 5.0 with a cam, im not sure why this is a problem, he have done many 5.0s and even without a tune, the a9l computer idles the car fine after about 30 seconds.

[Cajun JungleBoy]

Okay got a question for ya Jarrod. Since I think that manifold is coming undone, and I'm getting the great tractor sound from the engine aka exhaust leak, the fuel smell went away... completely.