97 E300 Diesel loss of power
 

I need help. This E300 Diesel will run fine for about 10 miles and then it loses power and shuts down. It will restart after cranking for a long time and run fine for another 10 miles. I've replace the fuel filter and the strainer in the tank. I noticed the last time I drove it that if I give it full acceleration it will keep going but it's like something is holding it back. Any help would greatly be appreciated.