Car not running right
 

Hi, I'm running a 91 civ with custom headers. And I am having an accel problem.
when cold I dont seem to have an issue but once the motor jumps up if I try to put any pressure on the motor it starts to bog.. and in low gear it will even stall out completely. I'v changed the dizzy and plugs/wires any other suggestions...

Also on a side note and may be unrelated. once the motor warms up and I am driving if I put pressure on the motor my rpms on my tach start to jump in relation to the bogging..