Hi I am new to the forum but my 2005 Mustang GT has recently started randomly going into its Engine Fail-Safe/ Limp home mode. It did it twice and I was close to home both times so I just 'limped home'. I then quit driving it and haven't visited the shop yet for fear of a expensive repair. Anyone having this problem? Ideas? Thank you in advance!!

 

It says in the manual that it does this when it runs hot but it has not registered hot or even a notch above normal. Again thanks for any help.

 

Have you tried renting the tool to pull the engine codes and see what it's saying? Autozone rents it for free I believe.

 

I actually own one but I havent tried it because I thought it only works if the check engine light is on?

 

No CEL? Hmmmm.... Can you tell us more about this car? Are you the original owner? Any mods? Mileage? Any other "symptoms"? History?

 

2nd owner. Only mod is the axle back muffler delete exhaust with resonaters only. About 44,000 miles. As for symptoms, The second time it went into this mode I was on the interstate and I slowed down and got off at the next exit (1.5 mi) and as I was coming down the exit the engine shut off. It started right back up and I let it rest in a parking lot for about 2 hours and then drove it home and it acted fine.

 

Also the gas pedal has been sometimes kinda unresponsive or slow to respond... I was told this was most likely the Throttle Position Sensor. And it would last "as long as i'd deal with it"

 

I had this happen to me twice in one day. Both times I hit the "reset" button on the trip computer and it cleared the Fail-Safe Mode. I had just installed a Bama tune a few days before so I called them to ask WTF they did to my car. The response was that it sometimes happens with a new tune. It never did happen again after that.

As for your issue, it still might be worth checking with a Scan Tool to see if anything pops up. There are a lot of transient things that can happen but not set a CEL.

I still say, "When unusual electrical things happen, start by cleaning the ground point attachments."

 

Thanks GTRaider! But to ask what is probably a stupid question... what/where are the ground point attachments?

 

Check the throttle body and sensors. You probably have a problem there.
But, do check for codes; even if the engine light is not on, there can be "Pending" codes that can help.

For a manual tranny car, things that can cause failsafe are throttle body (and its sensors/connectors), crankshaft position sensor, and a few others. For automatics, custom tunes can trigger similar issues with improper torque tables.