00 honda accord

I’m working on a 2000 Honda Accord EX 2.3L 4cyl that was given to me by my dad. I have yet to transfer the title and the tags/registration is expired. The check engine light is on and giving codes P0304 & P1399 - I have been working on this for some time now and have replaced everything I could think of from the spark plugs/ fuel injectors/ ignition coil and much more but I have yet to clear the light. I would like to take my car to the mechanic but I can’t drive it legally. Would I be able to get an exemption from the DMV for repairs in order to register said vehicle? What would be my best way to go about this?

Depends on your state. In my state I can get a temporary plate. I can call the insurance company and talk to them about my needs and they can accommodate. Even having it towed can be an option.


Simple , contact the DMV for where ever you are . Even if I told you what to do how would you know if I gave you correct info ?


If you ran a compression test you might know why you are getting a random misfire code and a specific cylinder 4 misfire code.

You changed a lot of parts that don’t relate to those codes.


I was asking particularly for repair advice in hopes to clear the codes myself.

I haven’t ran a compression test. I’m aware some of the parts I replaced don’t pertain to the codes but I’m not exactly a mechanic and all I see when I look up the codes are typically faulty fuel injectors, and spark plugs which I already fixed.

If it’s like my 1999 Civic, the engine has adjustable valve clearances. I would check and adjust those, especially if a compression check shows a low cylinder.

I have adjusted them many times on my Honda. Each time some have needed a tweak. The engine seems to run a little more smoothly when I do this but, yeah, the placebo effect may also be involved! BTW the car is still on its original valve cover gasket.

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You likely would have saved money by paying a mechanic to fix this car at the start.

A misfire code by itself with no other codes is typically ignition… which means plugs, coil, or an electrical connection. But, a low compression cylinder is also a possibility which is why you start there.


The valve lash on Hondas should be checked and adjusted every 30k miles maximum. With the plugs out compression should have been checked. If a cylinder (or plural) is dropping due to a tight exhaust valve then adjusting them may buy you some time until engine work is needed.

Once a tight valve is adjusted properly the engine may appear to run fine but it may be short lived depending upon how long that situation has existed; and it does not take long for valve face/seat damage to occur. In operation that often microscopic damage will be exacerbated by the hot gas exiting the cylinder and at some point the miss will be back with no quick, cheap fix.

You really need to run a compression test just to answer that question and the secondary question of whether to keep spending even more money.

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The 0304 is for a misfire in the last cylinder, but the 1399 indicates other cylinders are misfiring too. I think I’d focus on the 1399 first. Multiple cylinders misfiring means whatever is wrong is affecting all the cylinders. So beyond testing the compression in all four (which I’m guessing will show no problem) I’m thinking a problem with the EGR, PCV systems, as well as vacuum leaks causing a too lean situation. A fuel trim measurement would be helpful getting started.

Common sense says to do all the obvious stuff first of course, new spark plugs, new engine air filter, change the engine oil and filter, new fuel filter, make sure the crank sensor is working, and check/adjust the valve clearances. Avoid replacing parts willy-nilly, this can cause more problems than it solves, pretty easy to get a bad part right out of the box from the parts store. Then you have more problems than you began with.

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