i have a 1993 300D...I recently noticed an almost hissing like tapping when the car was at idle...i was told by a mechanic friend that one of the injectors was bad? he said it was losing compression...

my questions are...would this cause a reduction of mileage to the car...i am getting about 320 miles to the tank...that just seems embarrissing for a diesel...

also...is this an easy fix? can a DIY guy like me replace the bad injector fairly easily...if not...how much am i looking to spend to the part and labor?

thanks in advance...
Mario