whats good HT? tryna figure out why my car is misfireing at every cylinder. got codes p0301 - 302 - 303 - 304 - p01300 and p01399 sounds a little strange. .

anyway i got a 97 civic ej8 Y8 head w/ Y7 block.
so i'll try to explain the issue as easily as possible. car is sometimes hard to start but usually starts up normal, the idle is WEIRD. bounces sometimes from the lowest point on the tac to about 700 - 800 rpms. sometimes idles fine. sometimes doesnt even feel like its idleing at all tac will drop down to the lowest point and car might even die sometimes. most of the time the car will run good this is all completely random. also feels like theres some power being lost, i know my single cam dont got much but i just feel like it should be pulling a tad more.

so yeah, i changed plugs, wires, dizzy, cap, rotor, front o2sensor, and previously put in "Lucas fuel injector cleaner". plugs / wires / cap / rotor / dizzy were all replaced about 4 months ago, just put in the o2 sensor like 2 days ago. checked the earlier and they were all BURNT. they were NGK's 4 months old so i jus went and bought new ones and put em in. no change in performance.

any idea why i would have a misfire for ALL 4 cylinders? and any idea what i might wana look into next? maybe something with my fuel system? thx

 

vacuum leak at intake manifold. head gasket.