I have a 2000 prelude with the h22 motor. I bought the car about a a month and a half ago knowing it had the check engine light on it. I didn't think much of it because it ran good. I got the codes checked and they were P0131
P0301
P0302
P0303
P0300
Well I bought new plugs and didn't change anything. So one day I was driving home and as I was accelerating a kinda hard it started to hesitate really bad and a loud misfire from time to time. I drove it to the local autozone and they said I had a misfire on all cylinders now. The car would misfire in idle and especially when I pressed throttle. I replaced the ignition coil, and the distributor. Both did the same thing. It ran good for a little bit and when it got warm it started doing the same thing. So I drove it around the block, got it home, turned it off, disconnected the negative terminal to reset all computer and when I put it back on, it backfired loud as hell. So I just went and got sea foam, out it in the vacuum line going from the break booster to the intake. It's smoked and ran good for a while, and it actually stopped the misfire at idle. I drove it to the end of the street still smoking from exhaust running good, and it started to hesitate again. Drove it home, and at idle it hesitates again. Someone please help me!

 

Here are some things that can cause a misfire: bad o2 sensor, bad plugs, bad plug wires, bad distributor, EGR ports clogged, bad gas, out of spec valve clearance, bad fuel filter, bad cam timing. Since you replaced the plugs and distributor I would check everything else in the list.

 

/\ What he said. Do a valve adjustment and check egr ports.

 

I about to take the fuel filter off and replace it. But, I'm about to take the ignition coil off and then the egr valve, and I'm going to put seafoam in it and let it sit for about 2 hours. Someone posted about doing that and he said it helped a whole hell of a lot.