hi my sisters check engine light came on a few days ago and it gave me all these codes p0300 po301 p0302 p0304 and p0305 oh ya and a p1399. i know that cyl 1 2 4 and 5 is miss fireing could these be ignition coils? because the plugs only got 20k on them. we just put new belts along with timing belt an water pump, spark plugs and pcv valve. i noticed to sometimes when you put it in drive before moveing you can feel the car missing but this was before the light. my question is why is all these codes hitting us all at once? my sister says too in the mornings it starts up fine but once its warmed and you go somewhere and you shut it off you come back out you start it up and it either dies or has a rough idle. to me right there that its the coil packs but i could be wrong. thanks

 

Well, these are kind of fun IMO, yes that is a bad joke.
Two things that I have seen with this issue on these. More but we'll hope it is one of these....sorry, best I got.
1) "A" coil has gone bad. Yes I know you are getting multiple codes but once one mis fires the computer will then pick up the vibration across many.
2) EGR ports. There is a passage that can get blocked up, think Honda has a "kit" for the v6's that allows you to enlarge the port and instal a sleeve in an effort to prevent this from happening as much.

Now, I'll go out on a limb (= my guess) since this only happens once warm, I'll lean towards the EGR system......again, someone else might chime in, best I've got right now.

 

The multiple codes are like domino's in your situation. One problem = a book worth of codes.

I fixed a car with a similar issue.
I replaced EGR valve and such. Then everything was fine. No more codes.

Also, the ignition coils can cause the misfire issue that you speak of too.
But I would start with the EGR first.

Try changing out the EGR along with the gaskets and what not.

1. How many miles are on the car?
2. Did you gap the spark plugs if needed?

Was this an issue after changing out all of these items or before???

If everything was fine then you changed the spark plugs and now all of this is going on, did you replace them with the same ones that was in it before???

Also,

When some spark plugs get to a certain temperature they loose the ability to give a good spark. Causing codes and misfires to happen once the engine is warm. So you have to make sure to get the correct plug that is able to work at your engines normal running temperature.

All in all,

If the spark plugs are the same ones then go with the EGR

If not then make sure the plugs can work with your car.
Just because they fit doesn't mean they are compatible.

 

everything was fine before but this rough idle just happened only when the car is warmed up which is 20k miles later. i put in ngk's plugs. thanks. it really just started to happen after she gas up. we ran lucas treatment and ice heat and it still continues.

 

Did she get gas at a place that she normally gets gas?

Perhaps she just got some really horrible gas from somewhere which would explain the code P1399 which means that the system is randomly misfiring.

If only one coil goes bad, say on cylinder 1, then you would get a code like po301 which means cylinder 1 has a firing issue. But since you have po301 thru po305 then that means that a lot cylinders are having issues. Which can mean that you have bad gas.

This is a very weird problem that you have because it sounds like she just got a tank full of bad gas, but since it only happens when the engine gets warm, it makes me go

This is what I want you to do my friend,

Start the engine, warm it up real good. (Normal Running Temp)
Then turn it off, take the key out of the ignition.
Then put it back in and start the engine.

Right about now it should be running bad again.
Turn it back off again, take out the key again.

Take off the gas cap and keep it off.
Wait about 5 minutes with the gas cap off.

Keep the gas cap off of the car,
and after about 5 minutes with the gas cap off

Start the engine again while having the gas cap off of the car.

If the car runs normal with the gas cap off.
Then it is running to lean which would explain why it is running good when it is cold and giving trouble when it is warm.

Most likely the air fuel mix is way too lean.

Let us know after you have done that please so we can go further.

 

Did these problems start happening right after you installed the timing belt? I would double check that the timing belt marks all line up when the crankshaft is at TDC.

Multiple misfire codes can pop up with only one coil pack going bad. There was a recent thread dealing with this problem. When the car is running like crap, you can unplug the electrical connector to one coil at a time and see if the engine runs poorer. If you have a coil that doesn't change the engine, then I would suspect that coil is bad. Google ericthecarguy power balance test for a good video on how to do this.

I would also check that you didn't forget to attach any grounds in the engine bay as well.