Does the vehicle have a Mass Airflow sensor? One time, and one time only, I diagnosed a bad mass airflow sensor on one with similar symptoms. When you turned the key on, and the MIL came on, the vehicle would start. But if you turned it on, and the light DID NOT come on, the car would NOT start. After following procedures, I was led to the MAF sensor. I was instructed to UNPLUG the sensor and note the operation of the MIL. When the vehicle was not working properly,(the light DID NOT come on with the key on) I unplugged the MAF. When I did, the light came on. This told me to replace the sensor. I did and it worked fine. Wouldn't it be great if this procedure worked for you? Try it and see. IF not, re-post and we'll try another avenue.