Need some advice concerning a friends new to him Mustang GT. He bought a 2006 GT a couple of months ago. It has several modification including a Roushcharger and (I'm assuming) a tune to go with it. Last week he was driving when it started spitting (his words) and bucking. He stopped and tried to rev it. There was no throttle response, just idled and then died. Wouldn't restart so he called a tow truck. When the truck got there they tried to start it again and it fired right up. Still had it towed home and parked it. It's not showing any codes. Can anybody suggest a way to determine what kind of tune it has and what he can do to figure out what might be going on? Thanks

 

With that Rousch supercharger it is sensible to start with the presumption it has a Rousch tune. Unless you are into doing the work yourself (or himself), I would start with finding a Rousch dealer. They can check the tune. It might be a known issue that can be corrected.

 

Did a tuner (SCT, Diablo, etc.) come with the car when he bought it? Out of curiosity did he recently fill up with fuel just before the issue happened? If so and he didn't put in 93 octane it will likely cause issues. When I bought my GT in 06' it had a Roushcharger (1.6L) on it and the dealership (A Roush Dealer) told me it needed 93 octane. Also, is the charger the smaller 1.6L version like mine or the larger TVS style? The inlet tube on the 1.6L connects to the left side of the unit with the tube wrapping around the front and connects to the stock air box. If that is the setup and the pulley is larger and solid black it's most likely the stock Roush tune that came with it. If it has a custom tune it would most likely have a smaller pulley on it (possibly a 2.57) and a CAI instead of the stock air box. In that case your friend will need a tuner to see what's programmed in it. Otherwise a Roush Ford dealer as Paris said should be able to check it easily.

Here is what the 1.6L looks like in stock form. Ignore the text on the picture.

 

Good ideas. I don't know the answers (I haven't even seen the car yet). But i'll call him and ask the questions.
Thanks, Rich

 

Ok, scenario summary:
2006 GT. Modified with Roush supercharger.
Runs rough, goes to idle, will not respond to throttle, then dies (I assume as it's being stopped) (also not necessarily in that order, btw, but overall), will not restart.
Tow truck comes along, thing starts right up. Has it towed anyway just in case, and parks it.
No codes.

So with that info... In addition to these suggestions specific to the Roush setup, there's a few others that could be the cause. No start/dies can be the PCM (computer) itself, the ignition switch,the the cam sensors, the crank sensor, fuel pump, fuel filter... lots of things. Although pretty much all the things that'd cause this probably should throw a code, truth...

... except one, that is. No throttle response and down to idle sounds more like a throttle body issue than anything else, having had that on my stock '06. Almost exactly the same thing, although it didn't actually ever die, it just would go to idle and no throttle response, or would run rough, or both.

https://themustangsource.com/forums/...anyway-545892/

Read that and you'll see what I mean. In this case, the added mods are probably causing the dying of the motor on top of it all.

Like what's seen in that thread, I'm thinking the throttle body motor/gears/butterflies are not moving as they should. To expand briefly, the throttle position sensor is reporting the position as it should, but the computer sees the throttle isn't set where it wants it to be, or it's movin' around, jittering about, stuck low, stuck high, whatever the case may be... and it says "allright, enough of that, the throttle's messed up, we're gonna crash/break if I keep trying" and turns off the power to the throttle body motor. That automatically closes the throttle to idle/off, the default condition given the springs on it to close it. The throttle will no longer respond to input from the pedal until the problem is cleared, usually with a restart, but if the problem is that bad, not even then.

All you might see besides the symptoms you already see is a wrench light on the dash. Which I'd suspect he's got when it dies/goes to idle and doesn't respond, unless the Roush tune took it out. Be odd if it did, though. There's not any check engine light given for this condition. That's why there's no codes. Well, not necessarily any shown. There's perhaps a historical trend code that's not normally available when a 'regular' scanner is used and not a full blown all the bells and whistles scan tool instead where you can really dig in to things.

Just throwing this out there... it's possible the wrench light could be burnt out, or 'taken out' by the PO. People (siphon with a large amount of negative pressure) like that sometimes, unfortunately. One would hope they'd not bother doing that, but.... Turning the key from off and watching for it should solve that mystery of 'is it or isn't it good?'

For what all that supposing and previous experience is worth. It just sounds like that's the thing, given the description. Maybe it's just a bad wiring situation, as there's probably an extension from the original harness to move that throttle body over, so... maybe the extension is bad...

Hope that helps, good luck! And tell us what happens when it gets fixed, info's always good!