Chris,
I have been going through the same thing so I know your pain. I got an ignition tester from C+H and I am going to do some range checks with it to determine if it is ignition or vibration related. Since yours started after several flights it may be something as simple as a metal clevis vibrating on the threaded rod, I had the jam nut back off one of these and it reduced my range dramatically. I also have a small glitch that occasionally makes the plane drop a wing hard to one side. If it happens again I will try and remember which way it goes and then switch the aileron servos and see if it goes the other way. I know that is a risky way of determining the problem but it is very intermitant.

I also may send in my ignition and let them look it over but I think it's a servo, lead problem. One other question, are you using a reversing "Y" on your elevator?