Starting and Running Problem...

If the threads still work and tighten you could clean it up really good and apply a thread locker to it to try and keep it from moving. I use the red or green locktite brand. You can find them at napa or any parts store. This would just be a short term fix. If you need a couple spare rocker arms and adjusters let me know. I have quite a few and I could send you a couple for free.