Progress Thread Intermittent Starting With Theft Light On Continously Whether Engine On Or Off.

I have an intermittent starting problem and a theft light that stays illuminated (no blinking) 2001 Mustang 3.8l---tried disconnecting battery--then followed the owner manual instructions to let the engine idle to warmup--run ac for 2 min.--then followed instructions for an IM emissions test. Drove on freeway for 10 min, stop/go for 20 minutes. Let idle for many minutes in line at emissions test center. No warning lights for this test. Then tried to restart---Theft light returned---engine ran rough--but passed test---then died and would not restart---had to have vehicle towed---theft light has been continuously on --even when vehicle key removed.....

I sought some advice from a Just Ask mechanic and was told to go to the dealer and have a IDS scan performed and that is my only solution. Not sure what that might cost....I may have to have the car (that I like) towed there and am at their mercy....Other possible solutions out there?

Master baiter said:

My 98 v6 did this. It had the pats key. Thought my prob lied in the anti theft system. My car did it worse when it was cold outside but not when it was warm. Put a new battery on it and prob went away. Old battery never seemed weak but had a bad cell. Try that first before you spend all that money fixing the other.

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Thanks--yes worth checking...battery has been under strain lately ---receiving jumps and having to deal with the not starting issue over the past month---before that I had a bad alternator with a bad diode--that made the battery go absolutely flat several times. With the Theft light on constantly-overnight, it also seems to reduce the cranking speed the next day---and temps have been in the low 20s lately. Battery light has been on a few times at start up also...