Can't find reason for miss fire.

I have a 1995 tacoma 2.7 4x4 that has a miss as you accelerate starting at 1800 rmp and goes to around 3000. Once past that it is fine. I first had a bad coil I had to change and the problem started after that. I have changed the coil, plugs and wires, rotor cap and button, battery, maf(that's an expensive bugger), I also had one bad injector that I change and that helped but the miss stayed so I went ahead and changed the other 3. I am at a loss it is worse going up hill. Please help.

 

Also I had a plugged cat, so my mechanic straight piped it. Is that the cause, should I put a new cat on?