i just did a internall combustion clean and  changed my plugs with delco plat.on my 2.4 sunfire gt and since i put in the plugs its runing rough it goes in and out like the engine shakes constantly, but drives great .i changed the plugs again still the same cleaned the spark boots and the cover with my other one no change,any ideals let me know thanx. could the egr do this or o2 sensor.
sparky's fire
 
are the plugs gapped right and are the wires good you might  want to check the coil packs
Fast isn't always good, looks and sound is sometimes better
Imamarine