ecu and other prob

my cars ecu keeps beeping and my car also bongs alittle then goes but the engine light comes on after like 5 min?any help on what this could be? the check engine didn’t come on till after i put my headers on

what year is you car 90-91 or 92-93
if it 90-91 pull back the carpet and see what the code is, if its 92-93 there is a jumper wire on hte passanger side, not sure where or colors. but you jump them and watch the cel for the code.