Losing power/ stuttering while shifting

I have a 95 PA base with 145,000 on it. Recently it started to stutter while while trying to shift. I would have to floor it just to get going. I started this on the highway around 65, if i was trying to pass someone. A week ago it started to do whenever i would push on the accelerator going over 30. There were a few day I would start the car and it would idle extremely rough and then after a few minutes of driving would even out and only act up as stated above. I replaced the wires and found the first plug corroded, clean it up ,replaced the rest and it ran fine until tonight. After about 120 miles of driving it started acting up while on the highway around 60and going up hill. Any suggestions as to what else i should check besides changing the plugs? Thanks for your time
Andrew

The first thing you should is pull all the plugs for inspection. Look for any wet, or discolored electrodes that would indicate a fouled plug. Are you losing any coolant?

Is yourr check engine light on. I had the exact same symptons when when my egr valve malfunctioned. I took the same route to work and I would use my cruise control and It would never increase in rpm during the trip. But then would bog down on acceleration up small inclines and I live in pretty flat level area. took forever to go from 60mph to 70 it would just seem to flat line even though it would be at 3000rpm. But I changed out my corroded coil pack and all is well. It took about two days to clear up. I guess the uneven fuel burning clogged the EGR valve passages up over time.
I assuming the problem is fixed since haven't posted up.