The EGR solenoid won't cause any issues with the way the car runs even if it sets a code. The popping is caused by other issues.
The check engine light can be an annoyance, but it will come on and go off as you drive it, if it's only caused by the EGR system. If you can wait long enough, I will be freeing up a solenoid in a month or so, as my 7730 conversion takes place.
Did you replace the fuel filter with the new injectors install? I'm having what I thought was a misfire but could be described as sputtering and popping. It begins at about a half tank of fuel and gets worse as the fuel level drops. I am now theorizing that it's caused by a bad pump to outlet hose that begins sucking air as the fuel level drops below it. Filling the tank causes the problem to go away. Do you have a full tank of fuel?
Pat, I have a piece of hose that we can install before shipping.