This weekend I was doing some highway driving, nothing special, not beating on the car or anything. I was in 5th doing about 75mph or so and needed to semi-hastily pass a car. I dropped into 4th and gave it about 1/2 throttle...I start to accelerate as normal, then BAM, the whole car jerks and then continues running fine. It was violent enough that I actually thought I may have ran over something, but didn't see anything, etc. So I pulled off, looked everything over, didn't find any problems, so I continued on my trip. Wanting to do some testing, I dropped into 4th and gave it a little more juice...everything cool. Long story short, I downshifted and accelerated every once in a while, and was able to reproduce this loss of engine power 3 or 4 times, but not every time I got on it. I thought it might be bad gas, and I filled up at a totally different station (different brand, state, etc), got the same problem off and on on the way back. Its not throwing a check engine or anything, so I'm not sure whats up.
Its an 06, bone stock. I am putting 87oct in it. The most I have done under the hood was open up my intake pipe and look for the non-existant pre-cat contraption I put everything back together, tightened the clamp, etc. Car was not running when I did any of this.
I'm headed to get my first oil change sometime soon, so I figured I would take the opportunity to have the dealership explore, but I was wondering if any of you had any ideas about what could be up.
Thanks very much in advance. You guys have been very helpful!
Interesting I have had the same thing happen to me maybe 4 times in the last 4 months. Same exact circumstances. Although it felt to me like it went full throttle then off. I can't reproduce it though. Maybe an electronic glitch?
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06 GT all options, 5-spd, Tokico, Steeda springs, Saleen S/C, 10 lb pulley, 39 lb injectors, Autolite HTO's, C&L Racer CAI, Tune by Adam at ST Motorsports, 443.7 RWHP, 429.5 RWTQ
Back when mine was completely stock I could downshift to 4th at 70mph or so and floor it and it would fall flat on it's face for about 1 second then pick back up. I never did anything about it though because I started modding before I ever got around to taking it back to Ford to look at it. And it has not done it since I started modding and tuning.
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2005 GT Premium, all options.
Performance mods: Lets just say it's not stock
Some people are like Slinkies. They're really good for nothing. But they still bring a smile to your face when you push them down a flight of stairs.
It seems to have something to do with cruising for a while......in other words if you do stop and go driving ...youll never see it. Go drive down an interstate with the cruise on for 30 mins or so and downshift to pass a car and it rears its ugly head. I heard it had to do with the throttle -by-wire set up.....I dunno....
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2006 Mustang GT, Vista Blue, spoiler delete, premium package, Borla mufflers, C&L CAI, SCT tuner by Brenspeed, Hurst Comp Plus shifter, Steeda UDP, 4.10 gears, J&M lower control arms, Steeda adj. UCA, Raptor Perf. shift light, aluminum driveshaft....
Ack, if that is the case, then its just another thing about the fly-by-wire throttle that makes it seem like more harm than good. I recall a thread explaining the benefits of fly-by-wire regarding TCS and fuel economy, which is nice, but geez, I am definitely not a fan driving down the highway, downshifting to get that V8 power I paid for, and instead of getting my back pressed against the seat, I get a nice shudder....boooo.
I'll see what the Man has to say about it when I get that oil change. As always, thanks for the info guys!
Bone stock that fly by wire is a bitch. After the installation of some of my mods, I noticed less stall when dropping from 5th to 4th. Nontheless it's nothing to worry about its just the computer adjusting to the speed.
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05 Mineral Grey Manual GT, IUP w/ Charcoal leather int.
Performance MODS: 4.10's, Borla Cat-Backs, Steeda CAI, X-Cal2 w/93 Octane tune, JBA Equal Lenght Shorty Headers with Steeda HD Motor Mounts, Eibach Pro kit, Tokico D-Specs, 5.0 Pro shifter
This weekend I was doing some highway driving, nothing special, not beating on the car or anything. I was in 5th doing about 75mph or so and needed to semi-hastily pass a car. I dropped into 4th and gave it about 1/2 throttle...I start to accelerate as normal, then BAM, the whole car jerks and then continues running fine. It was violent enough that I actually thought I may have ran over something, but didn't see anything, etc. So I pulled off, looked everything over, didn't find any problems, so I continued on my trip. Wanting to do some testing, I dropped into 4th and gave it a little more juice...everything cool. Long story short, I downshifted and accelerated every once in a while, and was able to reproduce this loss of engine power 3 or 4 times, but not every time I got on it. I thought it might be bad gas, and I filled up at a totally different station (different brand, state, etc), got the same problem off and on on the way back. Its not throwing a check engine or anything, so I'm not sure whats up.
Its an 06, bone stock. I am putting 87oct in it. The most I have done under the hood was open up my intake pipe and look for the non-existant pre-cat contraption I put everything back together, tightened the clamp, etc. Car was not running when I did any of this.
I'm headed to get my first oil change sometime soon, so I figured I would take the opportunity to have the dealership explore, but I was wondering if any of you had any ideas about what could be up.
Thanks very much in advance. You guys have been very helpful!
-HypromanGT
I have something similar happening under different cirumstances. Mine usually does it when it's cold. I drive a couple hundred yards through my subdivision under very light pedal. As I get to about 2000RPM bam, it drops power just for an instant. But quite a jolt though, enough to spill hot coffee all over myself. It doesn't do all the time and it doesn't always have to be cold but it's usually soon after start up. I took it to the dealer and of coarse everything checked out fine, no codes. Even left it over night for them to drive it was cold. Nothing. I thought my it was something with supercharger but now I'm not sure...
When you all downshift, do you take your foot off the gas? I leave my foot where it is while cruising, and between shifts, the rpms raise and I have no power loss at all. The car takes off like a rocket. If you try it, be careful because you can get the tail end loose easily doing this.
Let me know if you find anything. Mine does the exact same...the dealer gives me the same old if it doesn't do it when we look at it, it must not really be happening. Kinda if a tree falls in the forest and no one is around does it make a sound kinda thing.
I had someone on the corral chime in and they said something about heat soak. You mentioned freeway driving. Every time this has happened to me I have been driving the car for a while on the interstate or highway and give the car some gas for whatever reason and it starts to buck and jerk. I have even looked for the traction control, but that isn't it. The light doesn't come on. Also, there is no check engine light, so no codes or anything like that.
I have a 92 Vette and it did the same thing until I put a cooler running thermostat in it. Since that car has an actual readout of the coolant, it would get to around 200 and cause the same kind of problem. I put a 180 in it and the coolant temps drop and it hasn't done it since. I'm not sure if it's the same on ours or not, but I'm thinking of looking into a cooler T stat and giving it a shot.
Please let me know if you find out an answer cuz this is BS. I'm thinking some of the cars have computers that are a little more finickey than others and that's why some are affected and some aren't.
That's what I like about this Forum, I thought it was just a strange quirk I had. My GT does the same. Always at the same point on the way home. I drive straight for twenty minutes on the highway, then take the exit to another road. Coming down the lovely PA. tightening spiral to the bottom of the ramp it gets dangerous (due to the merge lane being shared with a busy exit lane for the road you re merging onto). I will nail it here after downshifting, and I get nothing for about a second or less. Goes dead, almost.Then it kicks in. It feels like the rear drops,too. That could be the torque kicking in. I have found that I can reproduce it on this ramp every day if I try. Turning the TCS off does nothing. I have a custom tune in the car (Diablo 91 octane for the C&L intake). If I downshift more and keep the rpms higher, no power loss. But annoying never the less...
Hmm. Don't like the sound of this. I have the Roush charger but my GT is an auto. Been running it fairly hard but no loss of power, ever. I'll keep you posted.
It doesn't seem to affect many of the cars. I'm wondering if some of the computers are a little more picky and respond differently than most of the others do after the engine heats up a bit. I'm thinking of putting in a cooler t-stat and seeing if it helps. It doesn't do it very often either, which makes diagnosis difficult.
< Message edited by derck_mullin -- 4/16/2006 4:56:25 PM >
I experienced it a few times (like I said earlier) but only with an SCT tune. I got an Saleen S/C (with their tune) this weekend, and it did it alot. Cruising, downshift, gas, pow! sometimes twice. its seems like a very hard momentary fuel cutoff... ... if no one has any ideas I may call Saleen. I could record it possiblly with the SCT ... Help!?
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06 GT all options, 5-spd, Tokico, Steeda springs, Saleen S/C, 10 lb pulley, 39 lb injectors, Autolite HTO's, C&L Racer CAI, Tune by Adam at ST Motorsports, 443.7 RWHP, 429.5 RWTQ
Interesting...now a couple of people with tunes are mentioning this. So, it must be something in the computer that the tune doesn't change. Has anyone out there tried a cooler T-stat? I' thinking of getting a CAI w/ tune and swapping in a cooler T-stat. We'll see...anyone else? Hoping someone who has had this problem and found the solution will chime in.
Yesterday I did have it happen again, but this time it was the traction control. The feeling is identical, but since it's happened in fourth and fifth at freeway speeds I know it's not the TC every time.
Posts: 1087
Joined: 11/28/2005 From: Northern VA Status: offline
quote:
ORIGINAL: derck_mullin
It doesn't seem to affect many of the cars. I'm wondering if some of the computers are a little more picky and respond differently than most of the others do after the engine heats up a bit.
This is a thought, If you are having the power loss problem, post your PCM 4 letter code, Derck_mullin may be onto something here. Your Computer Code is on a white sticker on the engine side of the pcm (Silver box on the front passenger side of the engine compartment)
I usually baby mine around pretty much all the time, (23 mpg) but I got hard into it the other day, and mine momentarily shut down right at the bottom of each upshift. Felt like an inadequate fuel pump would on an old carbureted hot rod, only it was after I grabbed the next gear. Is this kind of like what you guys are experiencing? I read somewhere that the processor learns your driving habits, and tunes from there. I blew it off because I have a boatload of mods going on it next week. I hope that's all that's causing mine...
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Sudden/Quick loss of engine power - 
I put everything back together, tightened the clamp, etc. Car was not running when I did any of this. 
