When ever the engine is cold, i turn the car on and when i step on the gas to ride it hesitates and if i put more pressure on the gas it makes explosion noise. What can be some possible causes for this? i juts change the spark plugs, the wirering, and also the rotor in the distributer and the cap. i also changed the fuel pump, the castalist coverter.

 

Check your spark plug wells. Sounds like oil filled wells. You might just need a valve cover gasket change and maybe the lower seals as well below the rocker assembly.

 

Have you checked Oxygen Sensor(s)?

 

If it's happening before the engine warms up the oxygen sensor can't be a factor in the problem since it hasn't heated up yet.

I would think maybe leaking head gasket it letting coolant into the cylinder overnight and is backfiring as it burns off. Has your car overheated recently ? How's the car running after it warms up ? Any loss of power ?

 

Did it misfire before you replaced the sparkplugs, wires, cap and rotor?
Did you verify that the timing is correct?