CRAZY IDLE, NEED HELP ASAP

dirtyred11

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Ok guys, have a bit of a problem here. I drive a 2000 mustang gt 5 speed for all who don't know and lately I noticed that after a nice drive after I come to a stop the rpm's would drop and the car would try to cut off. It didn't do it as often at first but now it seems to do it more often and it doesn't just happen after a long drive anymore. What could be causing this? I also noticed that if I need to steadily get in and out of my car driving it ( I am a maintenance man so I drive my car from one point to the other sometimes ) it cranks different. It sounds like it's out of breath sort of when it cranks if that makes cense. Thanks in advance for all the help guys...
 

Ferocious

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it has been throwing a code for #3 coil pack being bad but I think that's related to something else.

If I were you I would fix this before anything else. A coil pack is like $5 at a junkyard. A spark issue could definitely be causing your issue. Also take a good look at your spark plugs while you're in there. Once you rule that out and have no codes, I would look at a vacuum line since they often don't cause CEL codes. Assuming all vacuum lines are good, clean out your MAF with some carb cleaner and a q-tip and then move onto your t/b, plenum, and IAC valve. I've had alot of previous idling issues and a new IAC valve has been the solution 90% of the time. I've already been through 3 of them.... but they're cheap so it's no biggie.
 
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dirtyred11

dirtyred11

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ScottyDsntKnow

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Uh... yeah that could be a problem... New plugs and see what she does. Also fuel filter and the stuff D3V listed.
 

ScottyDsntKnow

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Just get autolite 103s. These engines like running 1 range colder and they're $1.99 a plug anyway. Make sure you actually use a torque wrench or say goodbye to your threads. 12 ft lbs.
 
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dirtyred11

dirtyred11

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I already have a new spark plug and I have to find a way to keep it from setting down so low, I had to put another heli-coil in a little while back and now the spark plug sits lower than the rest. I went to check on it one day and found what you see so I know that is a huge problem. Could that cause the cutting off when I come to stops? It seems strange that this would affect that.
 

D3VST8R96GT

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Yes the a piston closing the gap is not good. On a 5.4 is no big deal cause the PTV clearance is like a mile but on the 4.6 is much closer but a plug that far in is insane! What was the cause for the helicoil?

Does it stumble and die or just die like you turned the key off?

Check out the 5.4 swap....

The D3V
 
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dirtyred11

dirtyred11

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Yes the a piston closing the gap is not good. On a 5.4 is no big deal cause the PTV clearance is like a mile but on the 4.6 is much closer but a plug that far in is insane! What was the cause for the helicoil?

Does it stumble and die or just die like you turned the key off?

Check out the 5.4 swap....

The D3V
I went to change my spark plugs one day and I got to the number 3 cylinder and it felt different when pulling it out. I pull it out to find the helicoil still on the spark plug so I finally found some at autozone and put it in. It was either fix it that way or let it just sit and keep in mind i'm new to the 4.6 so in my mind when this happened it was the end of the world but it got the car back running so I was happy. And whenever I come to a stop, say i'm pulling up to a stop light I fill the rpm's sort of drop and try to cut off. I then tap the gas to get them back up so it won't die and they dip again and I keep doing this until I come to a complete stop where I can give it more gas where it then levels out and quit trying to die on me. And I have given a 5.4 swap some serious thought, just don't want to try it and get in over my head.
 

Twista

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Get iac from the junk yard and try it on yours.

* Sent from tapatalk while sitting on the toilet at work*
 

ScottyDsntKnow

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5.4L swap is almost a 100% drop in but for my money I'd just get another 4.6L PI engine if you are having issues with this one and call it a day. Or pull the heads and have them timeserted. Or look into a LQ4 swap >:)
 
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dirtyred11

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Do you have access to a bora scope? No I don't, and this might sound dumb but I don't even know what that is. I do have an idea but not gonna say it because it might be dumber but wth, is it something I would look down into the spark plug hole with?

The D3V

5.4L swap is almost a 100% drop in but for my money I'd just get another 4.6L PI engine if you are having issues with this one and call it a day. Or pull the heads and have them timeserted. Or look into a LQ4 swap >:)
I have been thinking about all these options you have stated but i'm making this decision with the idea of what will be better for the future when I want to step it up later. So of those options which would be the better for now and the future? I was thinking the 5.4 but what do u guys think?
 

D3VST8R96GT

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I have been thinking about all these options you have stated but i'm making this decision with the idea of what will be better for the future when I want to step it up later. So of those options which would be the better for now and the future? I was thinking the 5.4 but what do u guys think?

Well what do you wanna do with the car? Upfront budget? And who is turning the wrench/what's those skill level?



The D3V
 

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