It's going to be hard to troubleshoot when you can't actually work on the car. I hope your issue is as quick and easy as carbs and wires, but the randomness of the cylinders tells me that it is valve issue. The fact that the valve seats do not hold up on these heads(original bronze) causes blow by and heat which causes carbon build up on the stems and cause sticking eventually. The fact that a valve stuck bad enough to dislodge your lash pad is a sure sign. I know, I fought this myself. When i took it to the machinist he said the seats about fell out of the head on their own. It's going to have to be done eventually, might consider yanking the head now and having it freshened up while your waiting for time to work on the car. I know it sucks because was running so well before, but it's just the way these engines are. The reward will be a fresh top end(bottom end should be fine) and some new life in a l24. What month is your car?