1998 Ford Explorer spark plug change?

Changed plugs and wires n this vehicle the other day took out autolite platinum and put inmotorcraft platinum and the car was running just fine prior to this other than a check engine light for a o2 sesor bank 2. The car now runs like it hs a miss in it and ll the plugs were gapped propery ad canged one at a tme as to not mi up the wires. Nowth chec engine light comes on and flashes ever so often it also no triped a DPFE code and insuffucent flow to the EGR. All of thes itemswere cecke about a yearag and were ok but as mentioned thvehicleran fine wih n roblems prio to the plug change the reason the plugs were changed was due to mileaqe and not knowwhen they were oneast but afte rpulling the plugs and loking at them the had een in a while