engine shut off while driving?


New Member
Mar 26, 2010
This is a 2003 4.6L

Today while I was coming to a stop, when i pushed the clutch in, the car ideled real low (500RPM) then shot up to about 1k RPM then died....it did this 3 times total, all while coming to a stop with the clutch pushed in. I have also noticed while I am driving at a steady speed the car feels like I am punching the gas pedal sometimes, when I am not....And then finally I dunno if this has anything to do with it but sometimes when i go to start it, it will turnover for about 3 seconds, in which I normally punch the gas pedal and then it fires up. What could be the issue? I was thinking maybe an issue with the TPS, and it just turned over 57k miles today.
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Not the Throttle Positioning sensor, when a TPS normally goes bad there is a drop in RMPs at wide open throttle, e.g. 5,000 then drops to 2000 all of a sudden w/the pedal pushed alway the way in then goes back to 5000. Symptoms of a Bad Throttle Position Sensor

at WOT it feels fine...I have only saw the issue when stopping (pushing in the clutch) and also while at a stop..it lowers the RPM's, surges up and then seems to stall...

Can I get an IAC or TPS at a local parts store like autozone or advanced? or would I need one from the stealership?
You can order an IAC at any autoparts store, even if thats not the problem thats a part that will go bad, so it maybe needed changing anyway. Make sure all of your vacum hoses are properly sealed, you can use a butane lighter to check for leaks and listen for RPMs increasing.
I checked all the hoses I could find. I didnt see anything that was loose/not plugged in, that was the very first thing I checked as I have had issues with vacuum hoses causing some weird issues on other cars.

I think researching it sounds like an IAC or TPS, and seems like the mustang is kind of known for issues with both....I might go ahead and pick them both up...
I wouldnt run out & buy parts it may be just some bad gas or a vacum leak check all the hose clamps & even put a new gas filter if there is no code it could nothing but bad gas try sticking to newer gas stations that do a good buisness ......check that gas filter when its off try & remove it gently & drain it to see what was in the filter mud water ?
I ended up cleaning the IAC, and I also noticed with the new intake the hose was a little too loose going to the IAC so I ended up putting a zip tie around it to tighten it....I dont drive the car a whole lot so I guess only time will tell if that was the problem or not.