I bought about a year ago a 1999 2.0 beetle with a 01M 4 speed automatic transmission. It has 114K miles and I have changed the automatic transmission fluid and the filter about 1K miles ago and when I did there where no large metal shavings on the bottom of the pan, just small amount of very fine metal sludge. The transmission shifts smoothly between the gears and no signs of slipping. The concern I have is that it seems like it does not go into 4th gear until the speed of car gets above approx. 38 mph. If I do local driving and stay below this speed it seems like it stays in third gear. I have been lousy gas mileage, about 18 mpg, and I would like to determine if this is the reason. Is this 4th gear shifting speed normal for this car? If not, what should I be looking at to correct. There is no CEL on.