It started doing this about 2 months after I installed it. It only does this on the 120hp setting. I have had other programmers that added even more power than the predator and never had this problem. It does not do it on the factory setting either.

I have a U7186 installed on my 2007 duramax lbz and it seems like it is defueling when it shifts especially between 3rd and 4th gear. Is this normal? It doesnt do it above 3/4 throttle, but anything less it feels as if I am letting off the throttle when it shifts. It is very annoying. I am running ...

The kit was from PPE and costs about 10 dollars. It includes 3 washers about .030" thick, but you only use 2 the other is a spare if you drop one and cant find it. It also comes with a nut to seperate the valve.

I have solved the problem! I ordered a fuel pressure relief valve shim kit and installed it today and the truck drives awesome. No problems shifting and no more check engine light. I is just bad to the bone! I guess the relief valve was dumping fuel back to the tank too soon creating a problem ...

Well please let me know what you find out. Thanks!

Yes, all of our trucks have the same revision, the latest one. So what is the fix? Lift pump?

Do I need a lift pump or a FPRV shim kit to get the full effect of the 120hp tune? I have 2 friends that have the same truck and the same predator. They both have the same issues on the 120 tune. We all have to let off of the throttle to allow the truck to shift to the next gear or the P0087 will ...

I am having trouble with my u7186 when set on 120hp at wide open throttle I get a check engine light and my truck goes into limp mode. I get the code P0087 which is fuel rail pressure low. What is causing this? When I have it on 85hp it runs great almost better than the 120 hp and shifts smoother ...

I have the U7186 rev 9r11 installed in a 2007 lbz duramax.
I was wondering what is a good setting to use on the fuel rail pressure at WOT and Injector timing. I have no clue what to set it on and what benefits I should get from these two settings.