After doing all that truck has been picking up to desired speed BUT it still bucks. MPG is still bad. Black Smoke is still coming out BUT not as much. but still smokes. So it still is running rich.

I hear knocking near the rear of the truck by the gas tank.
When i accelerate and hold it knocks constantly and the rpm goes up and down 2-4 lines.

I checked the fuel pressure with a pressure gauge. It goes up to 45 but jumps up and down between 45-49 bouncing faster as the car accelerates.

What can this be. I hate this

 

I am leaning front 02 sensor being bad.

And consequently, the cat.

 

I'm thinking that might be it too. Let's hope not. Tomorrow I will take it to the mufflers place and they can tell me if it's the cat and the sensor. Until then I'll cross my fingers.

 

Sensor is $50, cat is $75-100 depending on where you buy it.

I paid $160 total to have my cat and 02 sensor replaced.
Thank goodness for Amazon! lol

 

And if the cat is bad, tell them you wnat it back. I got a check this week for $115 for selling a cat I removed!

 

^And the shop didn't charge you more? Or did you install it yourself?

 

Need to unplug the O2 sensor to test it. Removing it from the exhaust is another type of test. With the O2 hanging in space, but still plugged in, it sees a LOT of O2 in the 'exhaust stream', and will consequently add fuel. Disconnect it, take it for a ride, see what happens.