Hi new to group. I just bought a 1982 C3 Corvette with the crossfire, of course. I right away replaced the plugs the wires and it ran pretty good. It idled well and had a good top end. For some reason, I wanted to check the EGR valve. When I put a vacuum pump on it, it acted funny on the first five pumps, but then held pressure after that. However, it was now stuck open. I think initially it was stuck closed. So I replaced it. it now ran OK, but was sluggish out of the hole you had to feather the gas or it would stall. I then replaced the O2 sensor because I was seeing a lot of black soot coming out of the exhaust. That is now gone, but it is still sluggish. I then set the timing this morning to 8BTDC and now it won’t start at all. When I turn the key I can hear fuel pump, but don’t know pressure. Can’t wait to get this thing running , but struggling to get it to wake up.