Well after 5k miles on the new mach 1.5's, my engine is still making a strange noise when idling. It sounds like someone is inside the cab and barely tapping the accelerator pedal, maybe close to a 50 rpm increase. It does it for a split second then goes back to the normal idling sound of a cummins. I noticed this noise right after the injector swap and kinda ignored it. It has gotten a little worse though. It does it once every 4-5 minutes of straight idling. It doesn't bother me, just wondering if its anything to worry about. When I installed the new fuel sprayers, I made sure everything was torqued to spec and the truck runs great. It does it with the comp on or off. Any ideas?

 

Just guessing...

But I would have the injectors POP tested.. Sounds like a bad / poor injector.

Since the problem started with the change of the injectors and gotten worse...

Just a wild guess...