91 PA idles rough

Hello
I have a 1991 PA/ultra & it just started idling rough today & is slow to accelerte.

I have just changed the plugs & wires.
when I changed the wires there was rust in two of the boots when I pulled the ends off the coil pack so I cleaned the terminals good before I put the new wires on but it made little difference in solving the problem.

I checked for trouble codes but none were stored & no SES light has ever come on while driving or at idle.

Does anyone have any ideas as to what might be causing this?

Thanks in advance, Roger

Have you changed the fuel filter? How many miles on the car?

Could be the coil pack and module, happened to me.Changed plugs and wires still Ran like crap til it just died 1 day , also make sure your wires are all on the plugs their suppose to be. Its easy to have 2 wires you thought were on the right cylinders until you checked it the 5th time.-Chris

In addition to what crys36 and hotz28 said, also check your PCV valve and lines.

It's a '91. In addition to all of the above, I have changed all the rubber vacuum hoses and connectors on mine. Seems like some elements of the engine systems run better on the correct vacuum pressures. I also replaced the positive cable, not just cleaning, made a substantive difference.