MrMoparMan

Looking for some ideas, I have ready through all the threads I can find and haven't narrowed my problem down yet.

A little repair history:

New injectors, ran great.
Then hard starts with P0088.
Replaced FCA, starts great and no more P0088.

Now a P0148 and no top end power. Still starts great and idles perfect, no smoke. The low end power is normal, but it has no power when I really get on it. It will rev slowly to redline but has very little acceleration.

I swapped in a rail pressure sensor from a good truck, and no change.
I replaced connector tubes because I had not done so with new injectors, no change.

Just wondering if there is something obvious that includes the P0148 and everything normal except for low top end power?

Thanks in advance.

BigIron70

Can you monitor the fuel pressure at the rail? Check the pressure limiting valve for leakage.. Fuel and air filter new?

MrMoparMan

Oh, I forgot to mention new air filter and great flow from the fass pump. I don't have a rail gauge, but I guess I can check the limiting valve. Is there a procedure for that?

MrMoparMan

I checked my fuel pressure relief valve, it had fresh fuel sitting in the top of it. I replaced it but have no change in my symptoms. Very normal driving other than lack of power on the top end.

Can anyone tell me what normal boost pressures are?

rjm022

been fighting the dreaded p0178 code off and on for over a year. my symptoms seem to appear more in cold weather also. i have posted here about this code before and have done what moparman has done but also to no avail. moparman- keep us posted please!

MrMoparMan

Well the truck is fixed and running super strong. It finally came down the the Cascade Overflow Valve. I think I should have changed it with the FCA. It is only 40 dollars and takes no time to replace.