help please. just freshened the engine. gaskets, camshaft, tune up parts etc. did a pile of bolt ons as well. front mount, ls1 mass air and translator, cold air, extender chip, injectors etc. it fires up but won't idle without feathering the throttle. cam was installed at zero. cam sensor was timed. it will occasionally back fire through the intake and will measure on the boost gauge. i'm going to retime the cam sensor to be sure. anyone have any thoughts? ideas? little frustrated and could use some advise. thanks in advance. the car is an 87 gn.