Ford Bronco II poor engine performance

I have an '86 Bronco II with a 2.9 fuel injection engine that has 140,000 miles. Recently I have been having missing, surging and rough running at driving speeds.

If you hard accelerate it seems fine. No sign of any problem at idle; other than idle speed is high around 1200 rpm.

I have replaced spark plugs, distributor cap and rotor and plug wires. I then used an auto-xray scan tool and it showed in-operative EGR valve. I put on a new EGR valve. Port into intake plenum was completely plugged and I cleaned that out.

With what I've done, it does run better but it still has signs of surging/rough running at driving speeds.

The fuel pressure regulator was replaced 2 or 3 years ago, so I don't think that is a problem

I looked at your postings and could not find an answer. Where do I go from here.