My Benz "Old Yella" had recently slipped a little in the miles per gallon dept. I have developed an obsession with the car and stay right on top of things mechanically so I was a little puzzled. The air filter was coming up on my periodic maintainence schedule so I decided on trying out a K+N. I usually change air filters after about 20,000 miles of use. This figure is flexible as all driving conditions are not the same. Dust, road salt and sand can all gather in the filter and constrict air flow which is essential to internal combustion engines. Well I put the new K+N in a little before the 20,000 mile mark and "bingo", that was it. The next tank of fuel I monitored for miles per gallon there was a marked increase in fuel economy and performance. This post is not a plug for K+N filters but more of a reminder to not overlook simple things like a clogged air filter if your car seems to be lacking a little in performance and efficiency. I for one however, will be using K+N from now on.