Could anyone help me with this problem? Got in my LS the other day and started it in the garage, sounded like it was going to start as usual, then it kinda studdered. So I tried turning it over again and the starter sounded different but wouldn't start. I could hear some exhaust coming out the exhaust and had my GF start it while I put my hand over the exhaust tail pipe. So the starter is working, turning the car over but not firing. I have replaced all 8 coil packs and the car has been running really well lately. Could it be computer problems, ignition?? Any help would be awesome.