TTaylor

I've got an 87 GT with include mac 1 5/8 equal length headers ,2 1/2 full exhaust ported gt 40 heads with new valve spring package,stock cam,professional products intake and 65mm throttle body.I've just had the head work and new headers installed.My idle problems is when in 5th gear or when the rpm's are around 1000 it will start jerking and then will smooth out and run fine .On take off it seems to run fine .Whats goung on ? I don't drive it much at all .Any thought would be appriciated.By the way i've already cleaned the idle air control but it's still the same one that came on the car.