1989 Chevy Celebrity Problem

I have this chevy celebrity that has a problem starting in the morning and when its warmed up it fine but still putts like its missing. I have changed the mapp sensor, oxygen sensor, spark plug wires, and I went to the dealership and tried to have the problem dianoist they said the problem was the EGR valve and some gas lines may be clogged well low and behold I changed the EGR valve and the problem is still present ( I don't know how to clean the gas lines). There is a vaccum hose going to the mapp sensor when disconnected the car runs good but I have to step on the gas to start. The last thing my mechanic can think of is the ignition coil. I am tired of shooting in the dark and the problem still presist. I am burning more gas now the ever before and the car smells like a gas station. Please if you have any resolution I would greatly appreiciate it.