I recently purchase a new 4 bolt main lt1 from gm. Swapped over all the accesories, intake manifold etc. Started up first try no problems. Bled the system and let it ide for about 10-15 mins. After that time when its completely warmed up it starts to missfire. If you shut it off and let it cool down then start it back up again same thing happens.Right now its at the shop that did everything But im lost as to what it can be. It only does it when warmed up. Has new oem plugs, wires.New GM Opti has about 20-25k on it. New oil pressuse sending unit and a few other lil things.
EDIT: 95 6spd camaro
jet hot jong tube headers no cats no air,no egr.
ory to a borla exhaust.
k&n cai
New clutch was put it
160 deg. t stat

 

if the miss only occurs when warmed up I'd look at sensors that only read during closed loop (o2 sensors, etc) or ignition devices sensitive to heat (coil, icm, etc)

would the car happen to be leaking any coolant?

 

edited first post with mods done

^ No coolant that i Know of or was told.
Ill mention that to the shop again but they said they would check into the sensors.

 

Found the problem. Injector as fubar. Car runs like a champ. Thanks for the help