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Discussion Starter #1
everything was pretty much perfect with my truck minus the random idle problems and the oil pan gasket leak. the truck has 79,000 mi and has been running strong. drove it around all day and it was fine. about an hour after i get home went out to pull code to see whats with the idle. grounded the STI and flipped the key on to begin the key on engine off test and relays click then everything shuts off and starts over again like i turned the key off and back on. turned off the key and ungrounded the STI tried to start the truck and it takes forever to crank over and when it finally starts it wont stay running unless i press on the gas until it kinda picks itself up then ROUGH idles at about 900 in park. so i shut it off and try to pull codes. this time i come up with what i believe to be "51, 22, 53, 54, and 35" thats engine off. i replaced TP sensor, MAP sensor, and ACT sensor. pull codes again and get the same ones. so i try to pull code with engine on and get "98, 22, 54, 51, and 53" what gives!!!!!! sorry for the life story i just dont know wtf is going on.

also when engine is on if i unplug the MAP sensor or the TP sensor nothing happens. if i unplug the IAC valve then it idles down but is still rough and throwing codes. idk if that helps. thank you in advance for any help!!!
 

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Ill post this in both threads you have to be sure you get it, but I would start looking at your vacuum lines see if any are chipped, or cracked or even straight broken. If so get some rubber fuel line and slip it all the way over the entire line and thats usually a good help to get you moving. I had rough idle, and threw codes like crazy til I fixed all my vacuum lines. It may not solve all your problems or any of them for that matter but it may fix all of them and its a cheap little upgrade to help ya out some.

You can call me tomorrow I will be at work but should be able to answer. Ill send you a PM with my number
 

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Discussion Starter #4
with all that i've thrown at it i really feel like shooting it sometimes. but when it was running i love this truck and i cant see getting rid of it. so fixing it is what its gonna be. marc pm'd ya back

ill take a look at all the lines tomorrow. funny thing is i have "replace all old crappy vacuum lines" on my to do list for my truck. lol
 

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Satyr of the Midwest
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Stop throwing parts at it, and start diagnosing. Answer WHY it doesn't make a difference when those sensors are unplugged; trouble codes do NOT mean "this part is bad, put on another one." Replacement is usually the last step in servicing.
 

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Vacuum lines won't cause those issues..

Without seeing it all in person, but they way you explained it all.. I'm going to pull something out of the air and say there is a possability you shorted out your ECU/PCM

I don't see how grounding the STI would do it, but who knows.. I'm way up here in Riverside but I have 2 ECU's you could try swapping out to see if it makes a difference..
 

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This is the second time in a week I've heard of this issue on a Ford....

Check the coil wires to make sure they are not broken or close to it....When they are nearly broken you will have similar issues.
I circled the wires I'm talking about in this picture. Sometimes they can be nearly broken right at the pin and you won't see it unless you are really looking for it.
 

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Discussion Starter #8
spectre- I was thinking the same thing about shorting out the ecu. I'm thinking of taking my ecu to a junk yard and testing it in a truck they have that works. thanks for the offer of testing the two you have but it's quite a drive for you to come out here. I'd hate to do that to you.

klake- I'll give that plug a check and see if anything changes.

thanks for all the help guys
 

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Discussion Starter #9
so i went out and got a voltmeter and tested all the "suspicious parts". MAP sensor came up perfect, IAC came up perfect, ACT i couldnt get a reading from idk if i was doing it wrong or what but i couldnt get anything out of the plug and the resistance on the sensor was perfect. heres where im stumped. still throwing codes for everything and and it all checked out EXCEPT the TP sensor. when i back probe the connector with key on engine off i get 4.97V at closed throttle and 4.97 at open throttle. i tried adjusting it like haynes manual says and nothing. the resistance on the sensor is perfect. its a brand new sensor. should i take it back and try another?
 

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Kitteh Commandaar!
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I don't have a book in front of me, but I'm pretty sure that voltage should change from 1-5 volts I believe...but yea, if you can't adjust it, then probably a dud...

KC
 

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Correct.. 1.5 - 5 volts.. A nice full sweep..

if it didn't change you might be on the wrong wires or it's bad..
 

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Discussion Starter #14
well maybe im doing it wrong idk. im putting the positive probe on the green wire and the black probe on the black wire and its giving me 4.97V. if i turn the sensor nothing changes. i just got a new sensor from kragen. and im probing the back of the electrical connector off the harness not the sensor. and again with the new sensor the resistance is right. maybe for some reason the computer thinks im at WOT the whole time whether i rotate sensor or not? im starting to think the computer it shot.

Marc how would you put that part in upside down? lol :scratchhe
 

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Discussion Starter #16
haha well im really starting to lean toward the ECU is shot. i tried it upside down and for the life of me the voltage wont change but the resistance will. so i guess ill just let beast sit until the weekend and we can see if Vic's ECUs work. ill owe both of you for the help you've given me.
 

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Ya.. spill the beans. =)
 
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