i got 93 eg coupe and ive just put in a 99 ls swap into it the swap was original in my integra and it ran hard with no problems now it runs fine but it runs rich and bad gas milage no check engine can any one help i searched but didnt find nothing close to the problem i have

its a stock ls but my old headers cracked so now iam running on a b16 header and cat but i still got the ls o2 in it can this make a difference and iam running on a stock civic fuel pump

 

what ecu are u running

 

ls ecu