High idle after coming home from track

DSG_03COBRA

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Hello everyone. I have an idle issue after taking my car to the track......
I recently took my 03 cobra with a 2.3 tvs to the track and the car ran great the whole time I was there! After doing all that I loaded the car onto the trailer with no issues.....The next day I unloaded the car off of the trailer noticed it was idling very high. It idles at about 1200. Checked everywhere for vacuum leaks and cant find any. I even tried spraying brake clean around all the hoses trying to find the leak. I can not find a leak anywhere and there are no CEL lights on. I thought maybe an IAC would cause this but since there are no codes for it, I'm guessing that's not the case. Has anyone else experience any weird issue like this with their tvs? I also have the dragon elbow on mine to. Any help would be appreciated! Thanks Guys!!
 

TheOneandOnlyLTstang36

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Try removing the hose from the intake tube that goes to the iac and check if it pulling tons of vacuum it should only pull slightly when at idle after cold start up once you get some heat in it


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DSG_03COBRA

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Try removing the hose from the intake tube that goes to the iac and check if it pulling tons of vacuum it should only pull slightly when at idle after cold start up once you get some heat in it


Sent from my iPhone using svtperformance.com

I will try that tomorrow. Unfortunately the car is so loud at start up, that I don't want to tick off my neighbors tonight. Is checking it for a slight vacuum just helping to determine wether or not the iac is bad or not?
 

jwcobra03

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If you have an idle screw on the TB, check to make sure the jam nut hasn't backed off. Had that happen before on my Accufab. Just something easy to check.
 
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CobraBob

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That would be my first check, as well. Interesting that it wasn't apparently idling high at the end of the track sessions, and started the next day on start up.
 

DSG_03COBRA

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I did check the throttle body and cleaned it when I was looking everything over. I didn't seem to be dirty or anything, but I cleaned it anyways. I also have the single blade gt500 style throttle body on it if it helps anyone to help me. Thanks for the help so far guys!!!
 

DSG_03COBRA

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Also I did check for a jam nut on the idle screw and there doesn't appear to be one there. The screw didn't feel like it was loose by hand or anything though. Is the vmp gt500 style throttle body supposed to have a jam not on the other side of it?
 

DSG_03COBRA

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Also is it possible my tps could've taken a crap and is causing this? If so, how do I check it?
 

01yellercobra

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I check the TPS by inserting pins into the wires and hooking my DMM up to them. Then slowly open the throttle body and watch the voltage. It should move smoothly through the range.
 

hotcobra03

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I had the sticking throttle body

Pushing on it would bring idle down l did try a spring but no luck

Had to replace it
 

FortLewisCobra

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I went through this following a dyno day and it was a vacuum leak. The PCV elbow on the back of the blower had failed, I would check there first as it's a common point of failure.
 

phil a

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IAC valve on intake elbow
See if it could have contacted the AC hard lines and dented the valve causing it to hang
 

DSG_03COBRA

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Well I finally got a chance to mess with the car again. I checked the IAC for dents and found none. I checked the IAC for vacuum and there seems to be ALOT there at idle (not sure if that's normal or not, I checked it right at the IAC). I tried pushing on the throttle body to make sure it wasn't sticking, and it doesn't appear to be.......Another thing I noticed was that it takes awhile for the idle to come back down when you rev it to. I'm not sure if that's relevant or not, but I figured I'd throw it out there. Thanks for the help so far guys! I really hope I get this figured out soon.
 

DSG_03COBRA

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I did check the pcv elbow on the back of the blower and it "looks" ok. How do I know if it failed? I think I may here a vacuum leak back there but I cant tell where its coming from (the exhaust is to loud with the high idle).

Does anyone know the part number for the correct pcv elbow
 

BlckBox04

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still sounds like something with the throttle body. vacuum leaks usually make the rmps a lot higher than just ~1200
 

Mojo88

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Since it hasn't been mentioned yet - I would recommend thoroughly cleaning the MAF. Spray the crap out of it numerous times and let dry (using correct cleaner, of course).

MAF may have picked up crud from track.............
 

DSG_03COBRA

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Since it hasn't been mentioned yet - I would recommend thoroughly cleaning the MAF. Spray the crap out of it numerous times and let dry (using correct cleaner, of course).

MAF may have picked up crud from track.............

I did try to clean the MAF. It didn't seem to help. I did use MAF cleaner when I did it as well. I ordered a new pcv set up for it. I can kinda hear a leak on it so I'm hoping its cracked somewhere that I cant see it. Guess we'll see if it works....
 

Mojo88

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Vacuum leak is my first suspicion, but other peeps already mentioned it.

Keep us posted please. I'm curious to hear the resolution...

Good luck............. ;)
 

DSG_03COBRA

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Well still no luck. I replaced the pcv hose and valve coming off the back of the blower. The only line I didn't replace was the one going to the bottom of the blower. The car did however decide to give me a code. P0507 (Idle Air Control System RPM Higher than Expected). Kind of makes me think the IAC is bad again.....Thoughts???? Thanks for the help so far guys!!
 

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