Intermittent Random Misfire P0300

[yungxrich718]

I have a 04 Sentra Spec V that just hit 100,500 miles today and for about two weeks now I have been experiencing random misfires. At times the car runs fine, it misfires but nothing crazy. Then maybe 10-15 miles down the road it gets all sluggish and has harsh misfires. The car is stock aside from having I/H/E. So far I installed NGK iridium IX spark plugs, cleaned throttle body and yesterday I installed two new OEM Hitachi Coils (eventually planning on replacing all four) when my moneys right. I installed the two coils in cylinder 1 & 2. Today i plan on playing around with the other coils in cylinders 3 & 4. Has anyone had this problem before with there Specs or altimas. Im fairly new to cars and plan on replacing fuel pump if this doesnt work and crankshaft and camshaft sensors. any advice will be GREATLY appreciated. Thank you

[yungxrich718]

Help! somebody,, anybody