I have searched all over the net for different answers not sure exactly where I went wrong.I went into the ecu and had no issues at first.I later tried to write a Entire,Then my car wouldn't start after that.I'm not sure what I screwed up but I'm hoping someone that knows about this could help me.The car is a 1998 ls1 car was swapped when I got it.The motor is from a 99+ the car has never thrown a Check engine light since I've had it.I am wondering since i put tunes on there was my car already tuned.I'll attach what I have...the car has TSP 17/8 headers and Rumbler dual exhaust.SLP LID LS6 intake 241 heads.Fuel pump has been upgraded not sure which one.Please don't kill me here I'm learning and trying.I read a good bit made a mistake hitting write entire.After that the VCM didn't want to read.Then eventually I got the VCM to read calibrations again. I hit reset fuel trims at one point not sure if that did it? Car turns over but will not start.Was just running fine earlier in the day.