You might get more help if you had just joined and posted in a focus forum.
It sounds like you lost a cylinder somehow. What happened before it started to run like this?
I second this. From a generic standpoint heres the diagnostic questions I would ask/post about on a focus forum as well:
-Are there any codes?
-Have you checked spark plugs/wires/coilpacks?
-If there is any issue with these or any form of misfire code, can you adjust the setup and get the misfire to move (this only
applies if you are getting a misfire)
-How many miles on the vehicle? Oil change intervals? Engine/Trans combo?
2003 Redfire & Black V6. Full suspension, 8.8 w/ 4.10s, tuned. 4.3L stroker + turbo capable of 550 hp soon
DD: 2015 SHO PP, 12.87 @107 1/4 mile (1.8 60') on 93 octane tune/CAI only. SAE corrected: 369.4/451.4 on E20, full Bolt On