Intermittent problem at highway speed (65-70mph) engine rpm drops a few hundred rpm then recovers. Checked fault codes and did not have any stored. This problem was happening at least once a day, so I checked plugs and they look fine. Checked plug wire resistance and they are all nearly the same with about 30,000 miles since last changed. Checked battery cable connections cleaning and retightening them and then I went through each electrical connector and unplugged and plugged them back in making sure they all had a good connection. Car ran fine for about three weeks and then on the way home from work tonight I had the same problem. Next thing I was going to check was the fuel filter/fuel system. Any tips are greatly appreciated!