Have a 2001 Chevy Blazer 4x4. While driving the other day, it just died. Rpms just dropped to 0, and wouldn't start back up. Pulled it home, and now it still won't start back up. Has a new motor from GM with only 12k miles on it. body has 180k. Fuel pump is fine, holds perfect pressure. Getting spark, checked each plug and each spark. Dis cap and rotor were replaced. ICM was checked to be good by autozone. It will crank and crank til the battery dies, and once in awhile you can hear it backfire. Every 3 or 4 seconds, you hear it backfire, then a loud click and all the lights dim, and then proceeds to turn over again, but never firing.