I am having a low RPM misfire and stumble ever since the cam install. I am running open headers now.. for a while I was having a hard time getting the car to idle.. until I idled up the idle screw and drilled the TB it would just die on startup. Anyways.. the idle is a little more steady now.. but I am having a horrid low RPM misfire... under 50% or more throttle it clears up... and under WOT it just screams. WOt feels perfect....

Was wondering what could cause this.. mind you I am on open headers and was wondering if this would have an effect on how the car's AF ratio was handling itself.. it seems to miss even before the car is warmed up tho.... before it goes into closed loop.. but like I said WOT and 50% or more throttle is fine.. about 3000 rpms seems to be fine...

Car will also backfire at idle and such.
Cam is Fm14.