I have a '95 5.0 that has recently had ignition/fuel/air problems (I think). When I slowly accelerate the car, I can feel it lurching and not accelerating smoothly. The RPMs flutter, bouncing around 100-200 (up and down) throughout the acceleration, and also while driving at a steady pace. If I punch it, the car will backfire repeatedly after about 4k RPMs.

I have taken the car to two different mechanics, and they could not figure it out. There is no read out from the computer that anything is wrong.

The car started experiencing this problem out of the blue; nothing was changed or modified on the car. Since the two trips to the shop, the car has had the following replaced/upgraded to try to resolve the problem:
- fuel pump (upgraded from stock to BBK 190lph) - the car had low fuel pressure
- fuel pressure regulator (BBK)
- coil
- adjusted the timing

The car recently had new rotor cap, spark plugs and wires installed during a previous tune up (about 2 months prior to this problem).

The car has the following upgrades that affect the ignition/fuel/air:
- BBK CAI
- BBK Throttle Body
- TFS Upper & Lower intake

Does anyone have any ideas what could be causing this? I am thinking of replacing the spark plugs and wires just for kicks (maybe one of them our fouled or bad?).