Ok, well recently when i start my car, and go at random mphs, and random gears it will just start to like buck.. and if i step on the gas it will have a hard time speeding up and make like a back firing noise coming from the exhaust. Well it only seems to do this when i first start the car, then when it goes away, almost like when it warms up, its fine, and it will not do it, but as soon as i turn the car off, and start it while its still warm or cold, it will do it again, Also, i just replaced the plugs thinking it was them, and its still doing it, wires also look fine, but who knows...

What else could be wrong??