Originally Posted by NRHX2002
I have a 2008 F-450 6.4L manual 6spd with a full 5" dpf and cat delete,
a 5"magnaflow filter back system, an Sct Livewire tuner, and AFE intake on it. Truck ran great for about 150 miles after dpf delete and tuner installed and then started studdering after 2450 rpm occasionally and thenthe check engine light came on. Then it started to get extremely bad and will not rev above 2450 rpm's in any gear. It falls flat on its face like a vehicle does with a speed limiter. The pedal has no response after the 2450 rpm.
ANYONE have a clue whats goin on?????? THANKS
What codes does it have? You said that it had a check engine light. That would be what you need to start with. I would bet that you are having a P0087 code (Low Fuel Rail Pressure or some such thing). This sounded exactly like what was going on with my truck when the high pressure fuel pump went out.
The tuning probably sent your already-flaky HPFP over the edge. It should be covered by warranty, but you are going to have to return the truck to stock - entirely. Some times dealers will argue over cold air intakes and tail pipes.