ok first off i have replaced Spark plugs(ngk v power), ngk wires, oem cap and rotor, oem fuel filter, pcv, cleaned out egr valve along with egr ports and passages, clean intake manifold, ran sea foam, replace both o2 sensors, got the valves adjusted, checked injectors. and still getting p300 p0303 p0304 p1399 car idle is rough on a stand still but once i drive it runs great. I got a compression test done and cylinders 3 and 4 are between 145-150 and 1 and 2 are between 200 -210, can this be my problem? any help would be great

Thanks

 

wow...that's quite a range. i'm guessing you're going to need to do a little bottom end work. i'd do some searching to see what all issues it could be. good luck

 

yea i know, and my question is now can this cause the misfires?

 

That I don't know. I wouldn't think so. It would run rough. What upgrades have you done? Have you tuned? Know if your timing is advanced or your air/fuel is lean?

 

Or have you checked for vacuum leaks? there's a lot of things that could cause your issue.

 

I have the same problem, my car is running too lean and I'm actually glad I read this post cause my car also started running rough today and my cel started blinking.

What I want to know is has anyone had the same problems and fixed it, cause I have seen alot of post's for this same problem and the same answers but nothing ever got fixed.

 

yea mine blinks also when im at a stand still, the only thing else i can think of is the egr valve or distributor. Can these be tested in any way?

 

I would hope if your egr valve was bad, the sensor would pick it up. If you've been running lean for awhile, they may have killed those two cylinders. i don't know how to check the distributor. i'm sure it's in the faqs.

 

yea i didn't get no egr codes, only one i got that i wasnt sure of was the p1399??

 

wow i had this exact same thing happen to my civic and yes i changed everything and all it was..........DAMN HEADGASKET

 

Sounds like you may have a blown head gasket. That's too much of a difference between cylinders. You should be no more than 10% between cylinders, IIRC. Sounds like the head gasket is blown between cylinders 3 and 4. Check your coolant overflow bottle while your car is running. If you see bubbles in it, then you have a blown head gasket. You can also take the rad. cap off and do the same thing. If you see bubbles coming up through your radiator, then your head gasket is definitely blown. A blown head gasket will cause misfires due to the fact of coolant leaking into the cylinder. Water doesn't ignite very well.

 

Those are all misfire codes. P0300 and P1399 are random misfires and the 303 and 304 are cyl 3 and 4 misfire. BTW, a flashing cel means the misfire is so bad its damaging the cats.

 

You've covered basically everything, and low compression is most likely thr problem. Do a leakdown test to see where compression is going.

Couple last things to try: swap distributors with someone and see if it changes, it is a possibility. Test fuel pressure.

Even if the problem lies elsewhere, you still have a compression problem to deal with when everything is done.

 

yea so i got a leak down test and it looks like the rings are worn on cylinders 3 &4, although the mechanic said he thinks the problem is elsewhere

 

I replaced all 4 injectors and cleaned egr ports and no Cel yet! although i do get the light flashing when im at a stop but once i go it goes away. any ideas?

 

You have low compression in two cylinders.

/

 

when i had this problem, it was due to the woodruf key being snapped in half, setting the crank position sensor off from the teeth on the crank pulley, this giving multipule random misfire codes

 

but why does the car only misfire on idle and not all the time?

 

Who knows.

 

this is the reason why it makes me think the problem is elsewhere

 

did mechanics do a compression test?