weapon r manifold......idles fine....ROUGH WHEN ON GAS

[ven0m319]

so i had to get a new manifold cuz my old one melted and was giving me a huge vaccum leak. i got the weapon r manifold, and put it on, ive been without a car for about a week now. so when it came down to the moment of truth turned it on and idled fine. but as soon as i gave it gas it was shaking bad and rocking bad. idk whats wrong now. im soo lost. can anybody help. i checked my spark plugs and my 4th one was real black. me and my uncle dont know if i have a bad coil pack or anything.

can anybody help

 

[Donutz]

A few things. First and foremost, make sure all connections are tight and your gaskets are sealing properly. When you experience this roughness is it immediately after start up? Did you reset your ECU? And have you monitored your AFR?