i have a 87 chevy 5.7 silverado..when cold it takes about 10-15 to start..when vehicle warms up no issue..here is what i have replaced..both fuel pumps..all sensors under hood including coolant and plug on the sensor..check plugs,fuel pressure is at 34 not losing a drop..replaced both injectors..even checked them for leakage..i am totally lost as to what else it might be..