Ok so here’s the situation. 09 v6 automatic. Driving normally one day. Got out of car at gas station while it was running. Came back car had stalled. Started right back up , idled weird and as I pulled away the wrench light came on.
so after reading endless threads on the web, I tried 2 different throttle bodies and a different gas pedal and nothing has changed. Now granted all the parts were used but what are the odd of they having the same issues. The car shifts fine , although it doesn’t seem to want to rev past 4000 rpm. All the gears hit including overdrive. It hunts at idle sometimes and will also hunt at cruising speed when you let off the gas. Only codes are o2 related which were caused by the wiring getting ripped in 2 from dragging. I did replace the plug on the harness side but I’m not 100% sure it’s wired in correctly because the wires weren’t the same color from an 05 as mine. But keep in mind this was like this weeks before the wrench light came on. I’m totally at my wits end with this. I’d like to find a schematic for the o2 sensors to verify that wiring is correct but again no luck. Any one have any ideas? I’ve also done the throttle recalibration each time I’ve had it spay and again nothing has changed. All I can say is HELP!!!

 

Welcome to the forums!

Here's the wiring diagrams you're asking for:
http://iihs.net/fsm/?d=40&f=Electron...20-%204.0L.pdf

This is the wiring diagram for the 2005 4.0L. I understand you're having an '09, but they should be very similar. If you need the specific '09, you might need to get a day pass to Alldata, or go get the actual 2009 Mustang shop manual. I still think this will help you out. You can also look, by going up the 'parent director' trail, at the 2011 version and see if there's much if any differences.

Past that, I don't know where you are, but you might need to get a good mechanic what has all the tools, either a Dealership or a private entity, because you can wind up spending quite the penny (and sounds like you've done so) shotgunning parts at the problem when it may be as simple as "oh, there's the ground that's loose right here". Wiring issues can be really stupid to trace.

I wish you luck, and hope that helps!

 

o2 sensors tell the car lean vs rich. You've been driving how long with fubar wiring to o2 sensors? Wonder if cat(s) fubar now?

 

Good point there, tbear...

 

So you have an OBDII reader?

 

Yes. Yes I do!

...oh, you're not talking to me are you...?

 

I had a similar problem with my 08 V6 with the pony package, not that the long package makes a difference but what mine was telling me it was not recognizing the rpm and the gear it was supposed to be in. This caused it to idle weird and but shifted fine, weird. I drove it home about 25 miles put the obd2 on it found the codes and cleared them. It did the same thing about a week later and I repeated the process figured if it does it again I will dig deeper. It has not done it for 3 yrs now. Knock on wood. I asked a Ford mechanic about it and he said it could have something to do with one of the sensors that deal with the throttle body or the transmission. I dunno if this will help but hopefully you get your lady back up and running I know the feeling and it makes your heart drop.

 

HA ha my Q was to the OP. :P

 

First thanks for the diagrams. They saved me. So it’s now fixed. I’ll tell you how I got here. After I saw the schematic I wired up the o2 sensor that had broken wires properly. Cleared codes started and ran car. Drove the usual 100 yards and the wrench light came back on. Back in the shop. Connected scanner. Had a bunch of pending codes. ALL the o2 heaters. The PCV heater, and EVAP codes. Sat down with the schematic and found all of these share the same hot source. Pulled the plug off an o2 sensor , found no power there. On a whim I opened the fuse box, started pulling fuses. Found one blown. Replaced it. Had 12v on the sensor. Checked codes. All were gone. Took it for a drive and no more limp mode. Came back checked codes. Nothing! She’s back to her old self. Thanks for the diagrams. You saved me!

 

Congrats! Glad you got her back to workin!