1992 Ford F-150 Misfire at idle

I've had intermittent problems with low idle and erratic RPM's since I got this truck. However, I had a rebuilt long block put in approximately 2 weeks ago, as the old one finally gave up the ghost. Since then, the overall driving has been a lot smoother. I pulled the codes after getting it back to try and clear the CEL. I received 1 for EGR valve opening not detected and O2 sensor reading lean in bank 1. Replaced the EGR valve, EGR valve position sensor and EGR vacuum solenoid. Cleaned the tube and passages best I could while I was at it. Changed the O2 sensor and cleared the codes. CEL disappeared and has not reappeared. I'm getting the bucking/surging which is a problem I've read with too much EGR gas. Going to put a restrictor plate in there to fix that.

The main issue I'm having is best described as a miss or hesitation at idle. Besides the above, I've replaced the distributor cap/rotor, MAP sensor, cleaned the throttle plates, replaced a few vacuum hoses (checked for leaks), checked the vacuum with a gauge (steady at 18-20), mechanic checked fuel pressure when the motor was put in (said at 40 PSI), new PCV valve and new plugs. Driving is fine, it only seems to miss at idle. I have not checked the resistance on the plug wires and I noticed last night that the terminal on the ignition coil looks rough.

Would either of these explain the idle miss? If not, what else should I look into? I plan on taking the entire intake off and cleaning it heavily in the next few days.