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Racing Idle In Park, Very Smooth In Drive

2233 Views 22 Replies 6 Participants Last post by  FullDuplex
I am in all over the internet to find a clue...Please, I need some brain storming...

When the car starts, idle jumps to 2K rpm, slowly goes down to 1K rpm and it stays there. While in park, when you give some gas, idle goes up to like 1500 rpm and HANGS there for 5 seconds and then starts going down.

There is no drivability issue, car idles very smooth in drive and traffic, it has nice pick up power, pedal is responsive.

I already changed IAC. TB and upper intake manifold is very clean. A month ago, I cleaned TB, MAF and IAC. Also attempted to pull EGR out, I was able to get two bolts out but the bottom nut didn't come out so I put everything back. Since then I had this issue.

I checked out visible vacum lines, seem like fine and ther is no hissing sound from anywhere in engine.

Appears to be car is getting much more air in park for some reason, it idles like Mustang in park, in drive it idles like MB...

Please help
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Another thing that , when I unplug any ignition cable it doesn't really affect the idle in park or unpluging TB position sensor...
I think I know what your problem might be. Do a search for throttle body flaps. And read the info.
Thanks for your input but, my idle problem occured suddenly.
If your hypothesis is correct, I shoud developed this problem over long run. Wear and tear doesn't happen over night.

All car manufacturers are using several TB suppliers and they all use the same material (brass, aluminum, cast iron, or whatever) and technology. Taurus TB is not unique for Ford.
I am focusing TB gasket, during reinstallation I used the same gasket. Air may be entering from TB + Intake connection surface.

Appears to be not many people can even give ideas...
I have the same problem. The reason the idle slows in gear is beacuse as the ford dealer said to me "There is a pot switch that lowers the idle when the brakes are on in gear ONLY" The IAC has been replaced along with it's gasket, the TB gasket has been replaced, I made sure the UIM seals were ok and retightened, the "set screw" type thing on the TB is backed out to where it JUST hits the screw when the TB plate is Closed. I did all this after seeing your Sticking TB and I had little to NO Carbon on the back of my TB. I'm confused and still seeking a source myself. I'll keep you updated if I find anything.
I have really done nothing to cause this issue other than cleaning the TB despite warning sticker, but I had to. It was all covered by carbon.

Hey Kermit, do you think MAF has anything to do idling in Park?
I think (this is an opinion you can look at this however you want.), it's not the MAF, I replaced mine last summer because of a stupid "resistor chip" incident.. I didn't know better basically. My idle didn't occur until recently. If it was a MAF problem it would throw a Code.. I think (my leak anyways) is after the TB, could be any number of hoses. The ford garage said they checked them, but I guess maybe they missed something.

I wouldn't be too worried about mine but when driving say.. 15 MPH the car will speed up to 30MPH by itself.. and this is going to make my brake pads wear fast and cost me money in the long run.

I am waiting for my car to cool down a little bit before looking at it today. If I find anything I'll post it here.
Here's an update on my ride. Well after the wreck I had with it a little black box type things fell out of it. I JUST found what it was, and it was NOT replaced! I hope this is my idling problem, but by looking around under my car I've found a lotta fluid everywhere. I'm going to go back to the Ford garage that worked on it and have them put it on a lift and show them the part that is missing, and ask why there is fluid EVERYWHERE, it seems to be a red color. I had the Tranny flushed, powersteering fluid, and Coolant. I know it's not the Coolant, and the Tranny fluid I think is suppose to be green. I'm going to try and get some pictures of where this is lcated, I have one but it didn't come out good.
No, tranny fluid is RED and coolant is GREEN. PS fluid is like a dark brown/red.
I found interesting articles about Coolant temperature Sensor. THis may cause high idle as well as pinging which I have....
I'll investigate this
Does the coolant temperature sensor malfunction or what? Mine reads around 200 degrees after the car is warmed up and has been driven a bit. (I can check this with my Autotap).

Here is a picture of my oil covered tranny, notice a couple of the Red arrows. The tube that is between the red lines is NO LONGER attached to anything.. and it is supposed to connect to something up above it, this was the piece lost in the accident. If anyone knows what it is that'd help me out.

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I can't see the picture, there is no link.
Coolant Temp. Sensor simply sends signal to PCM. If engine is cold, CTS tells computer to send more fuel to warm up the engine.

If engine is warm enough and CTS fails then it tells PCM "engine is cold, more fuel is needed". Of course more fuel means more air and high idle.
Well I don't know what the hell that above picture is all about. Here is the link to the picture. Leaky Picture I guess it resized the photo? That's lame.
I think i have the same problem, I noticed it started to happen after i started modifying my ride. I think if you get a chip for it that it should fix it. I think what is happening is the ram intake is letting to much air go through at an idle which is causing the computer to push more gas to the engine, if that is the case then the engine will rev higher in park until the computer thinks it has enough. Does that sound like what is happening? I am going to be geting a chip hopefully soon so i will be able to give you more info.
Scatman, that is pretty much it. There is for sure excess air entering to intake causing for PCM to release more gas. I don't think that I did something to trigger this issue, all I did was cleaning the TB...

It is very puzzling
Originally posted by Qwertz9586@Apr 30 2004, 10:47 PM
No, tranny fluid is RED and coolant is GREEN. PS fluid is like a dark brown/red.
PS fluid IS tranny fluid. If your PS fluid is dark brown/red, it needs to be changed. Use a full synthetic ATF, and make sure it stays RED.
Well, first off sorry if I'm hi-jacking your thread FullDuplex.

I cleaned the Tranny pan, and Oil pan today so I can see if the oil comes back and trace the leak back to the source, I think FORD just did a sloppy job, but we'll see.

Below is a picture of the Tranny pan (looking from behind the front wheel, at about the middle of the car, forward). The red arrow indicates where the next picture is taken, the black hose in the picture (The one that the red arrow goes through) is at the bottom of the second picture.

I think this is where the black box goes that I lost. The fuzzy tube that comes from the left side of the picture is about 1/8" or a little bigger, it is in the foreground, the open plastic oval just below the end of it, in the background attaches to the other part of the black box. I have no idea what the "black box" is called or what it's for or anything. I can't figure out what it is, if anyone knows It'd help me out a lot. Thanks!

* I guess they resize the images automatically.. well again that's lame click the link to see it actual size, sorry for the inconvenience*
Image Link 1
Image Link 2
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Kermit, no big deal about thread...

Just an update, I took my car to Autozone to see whether there was an hidden code in PCM, it came clean. Seems like Sherlock Holmes type misery.

Oh, is it my PC or what I still can't see those pics.
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