600 CAT, engine flutter.

Check fuel pressure,fuel lines,tank vents.
Start with the simple stuff first.
When was the last time the fuel filter was changed?
Which model cat E-C15-accert?

 

Yah I would check fuel filters I had to in the beginning of getting my truck change my fuel filters like every 2k miles I was using bad fuel . Didn't know it till a mechanic road with me and told me change fuel filters these cats love there clean fuel filters

 

what he said ^^^ fuel pressure test will be my first step if nothing has been done in that million plus miles. lines tend to swell up in side orings tend to get hard and torn and so on.

 

if you found one bad line I willin to bet they all are going south. if it was coming apart you could have debri jammed in the system some where restricting the fuel. some times you will get lucky and all debri will pass through and jam up in the check valve. simple fix just replace check valve. you will know when you pull it out and if you see little bits of black pcs of rubber in the orifices of the check valve.