Ok I've had this car for two months and only driven the for about 30min since i bought it. Everything on the car works, it just won't start. The starter cranks, I have fuel and air, but no spark. Mode 3 on the ECM gives a code 21(Ignition signal missing in primary coil). The coil has power going to it b/c i tested it with a multimeter. I tried starting it with 2 different ECMs they both gave me the same code. The last time it started I drove it for 15min then on the way home it cuts out and won't start up any more. I got it towed to my house and found out that the ECM was blown. I replace all the blown fuses and all the relays that i could fine. Change the ECM and put it mode 3; and i got the same code 21. I hope some one can help.

 

You might wanna try another ignition coil and possible an ignition control module. It sounds more like the module due to the fact that when they warm or heat up they fail when bad.

 

I have three coils that get 12.46v to 12.75v when the car has power and there all within OEM spec. where is the ignition control module?