92 Cavalier

I posted earlier about my 92. Took it in and it was diagnosed with a bad EGR valve. I replaced it. Vehicle will idle now, but sometimes, most of the time really, under a load it will start missing and running rough (seems like no power) again. The mechanic said that I needed to drive the car for a couple of days to get the electronics used to the new EGR valve(?). I cleared the codes, and still, the same thing. I am afraid to drive it because I dont want to get stranded on the road. We just bought the car back in November, so now we are stuck with it. I have read all sorts of posts like it was the MAP sensor(tried that one), or the IAC valve(it works fine). Replaced the EGR valve and still, pretty much the same thing. It seems to be a little better, but I still wouldnt trust it on the road. Im pulling my hair out in frustration because I sunk what extra money I had into the car.
If someone can guide me: My next plan of attack is the fuel filter and the O2 sensor. The garage didnt say anything about a bad o2 sensor code, so Im leaning more towards the fuel filter. It seems like it may be starving, but not all the time. I dont get it!!!!!!

Check the spark plugs and wires, and the distributor cap and rotor if it has one?