Consider your company extremely lucky. Every fleet I know that runs the mp8 has had injector issues at one point or another. I loved my Mack while I had it, but you said it perfectly, they are not fuel efficient trucks. Best I've ever heard with the mdrive was 6.5 running 65.
We may have more injector problems than I'm aware of. I don't spend a lot of time around the shop. My truck has been very good though.
@ChicagoJohn I am gonna go out on a limb and say they had to redesign the cup/injectors for the common rail system. If it's anything like the DD 15 injectors you wont have to remove the valve cover to replace an injector.
From my understanding the 2018 MP8 was a redesign from previous years. They are now common rail injection with 3 slave injectors. I'm not exactly sure how it works, but my local Mack dealer said it seems to have helped solve the cup issues.
I had a 15 with 505hp MP8. I took it to Nextran Atlanta and had them put it on the dyno. It put out 300hp to the tires. It should be about 375-400hp. They ended up running a bunch of tests, replacing the EGR, Turbo, and a 6 pack of injectors. Every time they said it was fix, but never was.
