getdirty

I am not sure what led up to this or what other work was done prior to what I have done. A buddy of mine purchased the bike in this condition and we are trying to get it back to running condition. 

Thanks in advance, 06 LT-R450, will start and immediately shut down will not idle at all. Fuel pressure is good, injector good, spark is good, also checked the TPS and it is good. While messing with the IAP checking voltage and such disconnected the vacuum line from IAP to the throttle body and it will start and idle just fine, any throttle input and it will spit and sputter and eventually die. reconnecting the vacuum line while it is idling will kill it. I swapped another IAP with a known working one and had the same effect. What would cause this? Does anyone have some suggestions on where to go from here?