hi,
i have a 98 monte 3.1 that is giving everyone a headache.

from beginning: died going down the road, no injector pulse. starts for less than one second and then dies. good spark, good fuel pressure, no codes. after much diagnostics and troubleshooting, reset computer out of desperation (disconnect battery overnight) it started right up next morning. ran great for 15-20 miles then shut off injectors again. replaced pcm and ran great immediately after for another day or so and same problem occured. switched back to original pcm, ran again. then same issue etc. no security light flashing, no codes, nothing. could this be security related?

 

i should add that the security light is not flashing. it behaves as normal. when it does die, if the ecm is replaced where it died, it will start right back up and run normally.

 

You probably ave a bad injector or crank position sensor,

Not sure if it is the same but on 3.4 DOHC when those drop a injector it cuts them all off,

To check them you will have to pull off the upper intake manifold and unplug the wires going to the injector then get a multimeter and check the ohms on all of then, they should be close to each other in the reading, i'll try to find the exact specs

 

just a side note: replaced all crank/cam position sensors. trying to get it to die in the driveway at the moment.......

 

got it to die in driveway. injectors still have power after car died, no pulse(ground). they will spray when grounded. closer to an answer!