I've got a 94 silverado that I dropped a five three 4l80e combo I can't seem to fire up on its own. The walbro pump is working I've got 49 psi at the rail 45 psi running and getting spark for sure since the only way it'll fire up is with a gas dripping rag over the filter.I have now way of pulling codes as I haven't wired my obd2 port yet. I know that my fuel pressure sounds low but its a flex fuel engine which only required 48 to 54 operating pressure. After I get it running with the gas soaked rag it idles just fine. After the engine is warm and i kill it and start it again it'll run on its own it's just the cold starts that are giving me trouble