the car is a 99 accord lx auto, 160,xxx miles.. had the trans and EGR replaced 8 months ago. A week ago my wife was going to work and getting up to speed on the interstate, at 55mph the car loses a little power and the check engine light comes on and flashes.. when she got home I scanned it and it came up with P0300,P0301,P302,P303,P0304 and P1399.. I replaced plugs, wires, cap and rotor, checked valve clearances, ran a bottle of lucas with premium octane and compression test (150 on all 4).
Drove it and about 55mph the light comes on and flashes but only codes P0301 and P1399 come up. Talked to a mechanic and replaced the distributor and injectors also rechecked the valves and spark. Still getting the 0301 and 1399.
Took it into a shop today and they said they looked over everything I did and it all looked good and couldn’t find anything else wrong with it but did get the codes to come up and also said it didn’t feel like the car was actually misfiring but was losing a little power. They said maybe it was a sensor getting ready to go out or something in the computer?
I have searched the forum and have already done what everyone else did… any other suggestions would be GREATLY appreciated!!! Thanks in advance!

 

I would clean the EGR port. On your engine, you have to remove the upper part of the intake manifold and the throttle body. The port for the EGR goes down the passenger side of the intake manifold to the EGR valve. Clean the part that goes into the throttle body and/or the upper intake manifold too.

 

i have a code identification for P0301=cylinder no.1 misfire detected=compression test it.as for the P1399 code i have nothing in my books for that code sorry

 

i will definately try and clean it out, i did take the plugs out and EGR valve and blew everything out while rotating the cylinders and got a bunch of exhaust soot out of them but i will try and clean it today. thanks!

 

the compression was 150 on the head on all 4 cylinders.
from what i found P1399 is multiple misfires.

 

So what ended up happening

 

This is another instance where the original poster didn't come back and help out others with the same problem.

You may want to send him a PM or an email through this site.

 

never found out what the problem was to come back and help anybody out with or I would have been happy to.

I took it to 2 different shops and they couldn't find the cause either, then the evap canister started leaking again after a year of having it replaced so my wife just went and bought a new accord because we couldn't figure it out and the car is now on craigslist.

 

Im having the same problem now, and I've been trying to read through some of these threads to get sone insite. I changed plugs wires dizzy and the only thing that stoppedit from stailing out while i drive was the seafoam and higher octane. Tomorrow I plan on cleaning the egr PORTS and now just the value as well as cleaning the injectors and the intake manifold. I appreciate the time administrators take to chime in on these issues. Unfortunately i don't have the option of buying a new car,so if these codes continue to come up i would love to hear more insight on my problem. Thanks!!

 

i know I did all of that stuff too and replaced everything that could have caused it and the shops double checked everything I did and couldn't find anything.. it will run fine if I clear the codes and drive it gently but as soon as you give it some gas hard It will throw codes.... almost like a limp mode or something.. I hope that you can find out what the problem is better than I did.