I searched both these codes, but has anybody gotten both at the same time? Running the Smarty at level 8. Fifty mile drive home today, about 10 miles in trying to accelerate on an on ramp, the truck didn't want to go past 2000 rpm in 3rd gear, backed off and seemed to run fine. About 45 miles in, truck on cruise control set at 70mph, down hill no load, the truck sputters and falls on its' face. Seems odd since the p0088 is a fuel rail pressure too high code. Got it off the highway and it died. I could not get it to restart until I unplugged the rail pressure sensor and plugged it back in. It restarted after a long crank then died after about 10 seconds. P0148 could be a lot of things, but I'm thinking either the fca or the pressure relief valve. What do you guys think?

 

I just put a fass 150 on my 04.5 cummins and it gave me these two codes And now my truck is doing the same thing my cel went away after shutting the truck of and has not come back on but it still dose the same thing I was wondering if anyone knew what the problem could be and how to fix it I also have a mp8