As the title says. It will fire but only for a couple seconds and then dies. Here's the set set up, new 525hp LS3 6L80e E38 and psi harness. Using HP tuners. Original tune was for a 2010 camaro 6.2 with auto trans.TCM has been married to PCM with GM equipment. Matched all the start and idle parameters to a 525 GM performance tune from the HP repository. Deleted vats and went through the whole immobilizer list in the DTC's. All physical basics checked. Switched and unswitched power to pcm. 58 psi of fuel pressure. Drained gas and added fresh fuel. Power at coils with key on, power at injectors with key on. Fuel pump comes on and stays on for 5 sec as configured in pcm. Turn the key and it barks to life for a second, maybe two and then dies. It will continue to do that. Went into the tune an re enabled Vats and starter fault checks. It does the exact same thing with vats enabled as it does with vats disabled. Fires, coughs, dies. I'm about 10 hours into this. Any help greatly appreciated. How to I attach tune? Thanks