We recently bought a 2003 Honda Element with 191,000 miles on it. It has an automatic transmission and it has a check engine light on. It runs good and smooth. After having the codes checked on it; it was saying a misfire on cylinder 1 and 3. We put new plugs, new coils and a new knock sensor in it. The check engine light was off for maybe 40 miles and then back on. Now the code shows number 1 cylinder and rocker arm actuator. While I was driving on the highway at 60 mph it acted like it just shut off; it didn't but that's what it felt like. It only last 2 or 3 seconds and then did it again a couple of miles down the highway. Same thing. It runs nice and smooth. I did not have the air conditioner on. What could be wrong with this now? We live in a very remote part of New Mexico with no known decent mechanics. Please help us!!! Thank you!