2005 gt failsafe engine mode

Slowpony1545

New Member
Jul 7, 2018
5
0
1
Chilhowie
Ive only had this mustang for about 3 months on the road. (A long rundown just so any possible reasons can be addressed) this car has been hit in the front end, it came from a auction only damage was passenger fender. After i fixed it and got on the road its ran only in the middle on the temp. Gauge (from what ive read it is only triggered on coolant issues correct me if i made a mistake) but when it triggers the failsafe mode completely at random it just goes into idle, no limp mode, nothing, i turn it off wait a couple minutes it fires up runs like a chamo. Is it a sensor? Do yall think the cras may have jarred something? Thank you for your time
 
I'm going to assume this is a 3 valve single over head cam (SOHC) 4.6 with a "drive by wire" throttle. This could be:
  • The throttle body itself
  • The throttle position sensor (the right foot pedal position sensor).
If looking for an educated guess the problem is in the throttle body. But it would help to have some more information to go on such as a DTC code. There are two position sensors inside the TB. The PCM goes into to limp in mode when the sensors disagree.

Disclaimer. I don't own a 2005+ Mustang. But I do work on a 2005 F150 with the 3V SOHC 5.4 drive by wire. So I do have some understanding of the system.

For cars with the advanced systems such as "drive by wire", IMO it's very hard to correctly trouble shoot without access to an ODB2 scanner. Something that can access, monitor, and graph operational PID's. An ODB2 scanner can also make short work of question like, "what is the sensor's value?". Graphing makes it possible to compare the values over time. Important when dealing with "soft" faults.

Here's some information on an affordable Windows based unit.

ForScan ODB2 scanner w ELM327 USB
https://www.stangnet.com/mustang-forums/resources/forscan-odb2-scanner-w-elm327-usb.57/

With this software it's very easy to graph the two throttle position sensor values and see if they diverge. Of course the problem could be obvious from the DTC code.

Here's some information that might help you to understand the problem. The video is by a very good Ford tech FordTechMakuloco

Ford Electronic Throttle Body Failures

View: https://www.youtube.com/watch?v=FDpUo3UPmto

Finally this thread was posted in the 1996-2004 model year section. There maybe people in the 2005+ MY section of the forums better able to help.
 
  • Like
Reactions: Slowpony1545
New member. Signed up. Post. Not heard from again.

Without any follow up it's hard to know if this thread is on point or not. Therefore it's not as useful to other people reading the forums that may have a similar issue.

Sigh....
 
  • Like
Reactions: Neuron
Hi yes, sorry bout a late reply was out of town for work some people around home say they've had the same issue out of a tps sensor so ive got that on the way i will try my best to respond quicker next time, as far as code she aint throwing nothing ‍ so ill start with tps


Thank you for the help and again apologies for no reply