Just did a engine swap in my 96 chevy due to some spun main bearings. Threw a cheap used 305 back in it. Got her up and running but runs like crap, or dies. Check engine light on. Pulled code. MAF input low. So I check for 5 volt reference. Its there. Check ground for continuity. Got the beep signal. Now I have one more wire. Which I believe is the signal wire to the computer. I don't know how to test it or where it leads for I dont have a ewd. I swapped a known good maf onto the truck also. No go. So Im pretty sure I messed up a wire......that third wire, which I believe it the signal wire. How do I check it? Where does it lead so I can run a new wire? Is there anything else I should be looking into before I find out and run new wire? Thanks and first post here.