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Discussion Starter #1
I just recently started having problems with high rpm's. The car would run great and just about die out 5300rpm's up,the idiot display will say = Fail Safe Mode, but no codes(I hooked my scanner up). I could turn it off and it would startup and run just fine(I do not have this problem every time). It finally just gave me some codes P2104 & P2112. I saw some old posts about TB taking a poop or the TPS did, wiring is fine not pinched either. I'm gonna open her up tonight and see if any dirt got sucked up. I do not have an aftermarket TB, the car ran fine after it was tuned. I'm wondering if the TB or TPS just happened to take a crap or not. Its becoming more of a consistent problem. It runs great until you get to those high rpm's when you getting on it.
 

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Discussion Starter #2
I just talked to my tuner and he told me to bring my car in tomorrow, he'll change a few perimeters. He said theirs something he needs to desensitize. Then will taking it for a test drive, I'll let you know how it goes.
 

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I had the same problems after a custom tune. The tuner said sometimes turning up the sensitivity will crap out the TPS. I bought a new one and have had no more problems. GA
 

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Discussion Starter #5
Will see, I'm hoping to have all the bugs worked out pretty soon so I can hit the 1320....
 

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Discussion Starter #6
Well no dice, He data logged the car and we went for a bunch of small runs and he changed the crap out of the settings. Almost everytime we get into 3rd gear under hard acceleration it does the Fail Safe Mode, then next run it runs fine. He told me its not in the tune, we went on a 40-45min test drive. He told me to check the unknowns like my autometer programmable shift light(disconnect it) He's seen them cause cars to not idle right. If thats not it then change the TPS and Pedal Sensor, he's done a ton of mustangs and has never seen this before. He said he's puzzled. It's sporadic and thats the issue. Why wont it cut out in 1st or 2nd, but will in 3rd? It sometimes leaves a code, but most times it doesn't.
 

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Discussion Starter #8
Thanks for the info if that was the fix, I replaced the TPS and I got 3 good runs up 5700rpm with no problems, hopefully that was the cure.... I just dont understand why 3rd gear was where it was failing? Will see this weekend for sure if its acting up or not.
 

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Discussion Starter #9
Well, the car is still acting up...... :banghead:
 

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Discussion Starter #11
Could be the throttle motor is failing or it could even be the pedal sensor.
I replaced the pedal and still have have the same problem. Do you suggest replacing the throttle body all together or can you buy the motor separately?
 

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Discussion Starter #12
Here's something interesting, I have a friend who owns a 05 GT with 80,000 miles on it(CAI, UDP and a tune). I just got back from swapping him whole throttle body assembly's. His is all original,TPS also. So I swapped them and took my car out for a ride.I was able to get five, 6000rpm passes out of it before it went into failsafe at 5500rpm. But then it was a 50/50 chance of it messing up after that. So I think my throttle body motor is getting weak from the car trying to suck the throttle body open. I'm ordering a GT500 Throttle body kit from American Muscle for my car. I'm really thinking that's the problem. It's sucking the throttle body open and that's throwing off the computer looking at the voltage between the TPS and Pedal. So im thinking going from the twin 55mm throttle body to the twin 60mm will let it breath better. What do you guys think? I will re-post what happens.
 

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Discussion Starter #13
I replaced the stock GT throttle body for a GT500 throttle body kit from American Muscle for $300. Im very happy with results. Hope this fixes it for good. Livernois racing and Bama at AM told me that swapping out the throttle bodies had a 98% chance of fixing my issue. Great advice.... :bigthumbsup
 

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We found the fix for this today without spending $300 for a TB.

Been fighting it for WEEKS! There was a hardware change at Ford AND a software change that hardcoded some parameters.

The reason the other TB worked for a while is because the ECU learned and adapted then failed again. We had a car on the dyno for 2 days non-stop troubleshooting.

But, hey, if the TB fixed it. GREAT! 10 possible extra HP. Thanks for your post on this. I found it the other night. And if you talked to Joe or Bill at the Magnuson trailer during the Power Tour...they filled me in. THANKS AGAIN :bigthumbsup
 

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I had an engine shutdown after acceleration. Check the voltage to the throttle motor. It should be 1.88 to 1.33 VDC. I had the problem after adding a throttle body. There is a brass adjustment screw on the left side under the motor on the throttle body. My problem and engine lights went away after I tweaked it.
 

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Hi, I have the exact same problem... (P2104) what was your fix?
I have a new TB, TPS & Motor and it did not fix the issue.
Your help would be appreciated, regards, Vic.
 
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