My truck has low power and a lack of acceleration, what could it be?

The engine seems to idle perfectly fine and also when the car is in park and the throttle is pressed it seems great. The problem is when i am driving it takes off from a stop very poorly. I cant even spin the tires. I have replaced all plugs, wires, cap and rotar. I have also removed the catalatic converter and changed the fuel filter about 4 months ago. I am thinking that the timing chain is bad but am unsure because i dont have a timing light. There is no check engine light on what should i check?