Chrysler Repair: 96 Concorde 3.5 L dies after 15-25 seconds, fuel pump relay, car wont start

Question
Car start and dies for about 15 to 25 second running.No code,ASD and Fuel pump relay power ok,PCM been replace due to no spark coming from ignition coil(Bad ignition coil driver).Now we got good spark and good fuel delivery.I notice that when turn the ignition off and then crank engine its run,(15 to 25 sec.)when it dies w/o turning ignition off position and start again car wont start.Any idea that can help us is really appreciated.
Thank you
Primo

Answer
Hi Primo,
Your observation about the ignition switch leads me to wonder if the switch might be flaky. Try testing for voltage on fuse #18 behind the dash (remove cap on left hand end of dash to access) as that is powered from the ignition switch and it feeds the PCM. See if the voltage drops out when the engine dies. If it 'holds', then the switch is OK.
Roland