93 LXE 1.8 surging

Ok I have a 93 Escort LXE which is the 4 door sedan that has the GT Engine and Transmission. It was running like a top, but it began surging slightly under acceleration. At first it felt like it just needed to have a good tune up, but I have completed that and it hasn't gotten any better, in fact worse. I ran the check engine light and got a EGR flow malfunction, however I pulled the EGR valve off of a spare motor that was running just find with no succes. I have replaced the fuel filter as well as the tune up. ANy suggestions.