1998 honda crv misfire code 0303and 0304

The OBD-II error code P1399 and P0141 for a Honda CRV 1999 are as follows:
P1399 - This code indicates that there is a problem with the misfire detection system in the vehicle. This code is often accompanied by other codes that indicate which specific cylinder is misfiring. Causes of this code could include a faulty ignition system, a clogged fuel injector, or a problem with the engine control module (ECM).
P0141 - This code indicates a malfunction in the oxygen sensor located on Bank 1, Sensor 2. This sensor measures the oxygen content in the exhaust gas after it has passed through the catalytic converter. Causes of this code could include a faulty sensor, a damaged sensor wiring harness, or a problem with the vehicle's computer.
It is recommended that you have a certified mechanic diagnose and repair these issues to ensure proper operation of your vehicle.

If it was just cylinder 2 or 3, the code would be 0302 or 0303. Instead, you have random misfires (probably) such that you should be checking things that affect the whole engine. Vacuum leaks, bad plug wires, bad coil(s) or ignition module are most likely, but even clogged exhaust, O2 sensors and bad battery can cause these problems. Yes, a battery can be good enough to start your car but still be bad enough to affect performance. If I had to guess, I would start by testing the ignition module. Most parts stores can test this if you remove it and carry it to them.

Yes, do check the coil by pulling each wire from the cap to find which one is not firing. It could be a cracked distributor cap also.

Check compression and timing belt. If belt is ok and you have compression, check to see if you have a pulse at the injectors. You use a device called a NOID light (basically a light bulb that plugs into the injector plug. Unplug the injectors one by one and plug the light in then crank the engine. Light should blink on and off if the system is working properly. If not check for a bad crank sensor, blown injector fuse and wiring harness. Hope this helps.

have honda crv1998 check light came on and when i stop on the red light the car starts to shake what can be the problem

I had a similar problem with my Dodge truck.I replaced the cap, rotor, plugs and wires and the check engine light went out. Within 4 days the light came back on with codes for multiple misfires..To make a long story short, I put electrical tape on the wires to adjacent cylinders and the problem was solved. Answer; The pluig wires they are making for Dodge are really cheap!

your clutch is done

recheck the plugs and wires check for proper gap on plugs also check that wires not crossed and that wires are properly seated on cap and plug

P-0304 indicates number 4 cylinder misfire. Are you using Toyota parts dept spark plugs? More often than not, non-toyota plugs make the v-6s run poor, right out of the box....
Try this:With the engine running, pull the connector wire off of the #4 injector. Note to see if there is any change with the idle quality. No change? You may have a bad injector.

make sure to have your mechanic buddy check for correct firing order
and engine compression becasue any thing mising in the cylinders eill cause a misfire code,
and what codes are you geting?
idont belive than you need an 02 sensor because with a present misfire teh o2 sensor will read rich or lean but most likelly rich