99 jetta 2.0 check engine light

I bought my jetta last year it now has 80,000 Miles on it and the check engine light comes on and off occasionally. It runs at 7500 rpms at a speed of 85mph is this normal? or Should i get the tranismission looked at. Also if i rev my engine there is a light rattling sound near the drivers side.

That is way too fast for 85 mph. Definately get the transmission checked out... I'm assuming it's an automatic? The light may have something to do with that, but it's way too early to say with what you've included.

the 2.0 does not rev to 7500rpm.