1999 Mustang Gt--dashes On Odometer..help!

[Migo]

I have a 1999 Mustang GT that turn over fine, but it will NOT start up. Theft light flashes rapidly and has dashes on odometer. I let it sit for 2 weeks and then jumped it off and it started up! as soon as I disconnected the jumper cables....it shut off and will not start. the battery is good getting 12.8V and fuel pump it cutting on. Please help!

 

[Az Pete]

Battery should be 14.5 volts when running. I would check the battery and alternator at a local parts store......it is free.

 

[wmburns]

+1 on above. Today's cars simply will not work right without a strong battery and charging system.

Also double check the battery negative terminal and the grounds around the radiator core support. Are they clean and tight?

 

[Migo]

Guys,
thanks for your responses! I have been out of state working, but will be back Saturday to check all this out and will keep y'all updated!

 

[Migo]

Just an update. It turned out to be the computer. I disconnected it for 5 minutes and reconnected it and it fired up. It only ran for about 5 minutes before shutting of and theft light flashing again. I replaced the computer with a new one and I've not had any issues with it.