I appreciate you chiming in and offering your .02

I think you may be right but I will give it another shot and be extremely thorough this time when I clean them. I followed the same procedure as this video:
I just made a few minor alterations after speaking with Mike from FIC. Instead of using carb cleaner I used non chlorinated brake cleaner. I also used a 9v batery instead of what that guy used in the video(12v?) Lastly, I never reverse purged the injectors like he did in the video. Maybe this time I will reverse purge them first then purge them the intended direction.

Now that I am pretty sure its only one injector thats causing my issue I will spend a long time purging it instead of doing it a couple of times. When I removed the injectors there wasnt any goo which people have noted when using e85. I wonder if ive just got some dirt caught up in there?

I know self cleaning them will not work as well as sending them into FIC but its worth a shot, not so much in the money savings but in the fact that my car wont be down the couple of weeks while I send them in.

Do you have any tips or tricks to cleaning the injectors?

 

Any time man. and yeah it cant hurt. As far as cleaning them I've tried to clean them the same way you just described and with gas I have had really good results like almost always works but with e85/ alcohol its a crap shoot lol. my friend runs his car on m5 methanol, to clean his he loads a gas map runs the car on 93 pump then takes them out and cleans them its a lot of work but because the methanol totally ruined a set of injectors he does it. He had to buy a new set of 8... big $ so now he goes nuts cleaning them.

 

Interesting. From what I have read methanol is much more corrosive than ethanol. I didnt back purge the injectors when I cleaned them a couple of weeks ago so I plan to try that this time around and see if that helps. I believe each injector has a little filter on the top so my thought is that by back purging them itll shoot the crap from the bottom of the filter out the top of the injector, rather than just purging them top down which should have helped clean them but probably didnt help free up the debris from the filter of the injector.

Just out of curiosity, do injectors ever go completely bad or do they usually just get gunked up?

 

they get clogged all the time but they can go completely bad, like I said my friend had 8 little paper weights they literally wouldn't do anything fluid would not go threw them at all. He sent them out and they couldn't do anything with them either they were that bad. O and the kicker is that they were only 4 months old! I think the best thing you can do Is just start the thing every day or every other day that helps a lot.

 

So you swapped the injector from cylinder #3 into cylinder #2?

Have you read the description of the P0300 algorithm in the factory service manual? It looks only for changes in RPM to decide when a misfire has occurred. It doesn't attempt to directly assess the operation of the injectors (e.g., it doesn't check the voltage applied to the injectors). So the only way an injector can cause a P0300 is through a lean or rich misfire. Perhaps you already understood this, but just wanted to be sure.

 

Using my tester they all seemed to function properly as in they didint leak and when I applied voltage and pulse them they sprayed the fluid nicely so they are definitely still working fine. I think there may just be some gunk in them which is causing some flow issues.

Fred- I have not looked into is so thank you for bringing that up. I did swap the location of the injectors. If its determining there is a misfire from either a rich or lean condition how would it narrow it down to a specific cylinder?

Now that you mention it, we tweaked my fuel map over the summer and added some additional fuel because it was running leaner than it had been originally tuned for. I dont remember specifically but i think it was around 12.2 during spoolup and we dialed it back to 11.8 (e85 BTW) We thought it was strange that it had changed but didnt think too much into it.

Now that Im running on my 93 map again I havent been beating on it so I cant tell you what my AFRs are in boost, but it does seem to idle lean(15-16). Shouldnt the idle hover right around 14.7?

My injectors werent gunked up and seemed to function properly but I have yet to send them in to be professionally cleaned. If they are indeed a little dirty getting them cleaned should richen things up.

 

Did you ever fix your issue?? i'm in the same Boat right now.. P0300/P0303.. -_- 05 evo 8

 

Hey sorry to hear about your misfortune and I apologize for not updating this thread. Unfortunately I have yet to figure out my issue. I pulled the injectors again a couple of weeks ago and gave them another cleaning. They looked pristine so I really doubt there is an issue with them. Unfortunately I have not had a chance to send them in to be professionally tested at this point since I DD my car.

The only code I get now is p0300 and it seems to only be thrown when I hit some traffic and come up to an idle. The car drives fine so I am pretty confident that its a phantom misfire issue. Only after confirming the condition of my injectors will I delete the code altogether.

Also I bought a compression tester about a month ago and checked my compression.
1-190 2-182 3-186 4-190 which seems to be great. Those numbers were with a warm engine, cranked with the throttle held wide open and the recorded number was what the gauge read after multiple cranks with the pressure no longer increasing. I say that because some people suggest 3 cranks or 5 cranks to get a number. Nonetheless the numbers are well within an acceptable variation.

 

^ yeah my car is doing the same thing. But only throwing P0300 codes. And its usually on cold weather and low rpm at higher gear.

I have ECUtek, does anyone have the ROM to disable P0300 ?

 

I'm in E85 and in Cold Weather 40-50* its near impossibly to start the car, if i leave it outside the garage.. i spend about 10 minutes, literally, trying to start it. another thing, when the engines cold, i NEED to let it warm up to operating temps for it to drive right, if not it will BOG and want to turn off. Even when i get to work, 8am and leave to lunch at 12:30 i need to let it warm up or else it WILL BOG and want to cut off. Codes are PO300 and PO303.

And i Personally think "OPS" problem is his Transmission. 03-05 5 Speed trans were notorious for throwing a random PO300, from what i'm reading because of the gear ratio in 1st gear, causes complications with the knock sensor, which senses KNOCK and Throws the Code. This was later addressed with the revised 1st gear in the EVO9 transmission, according to ShepTrans.

 

I know mine is an actual MISFIRE problem tho because i hear the "Pops" at Idle, plus the Hard morning start, plus the BOOST CUT after having the pedal to the metal more than 4 seconds..

Any suggestions? My first thought was ignition issue. Replaced the Plugs with the correct Copper plugs, Changed cylinder #3 Coil, wires looked good so didn't bother. Now i have a feeling and i'm putting 2 and 2 together, and feels like an injector might be going bad, or is clogged.. E85 tends to clog them, from what i read. I'm going to make another thread on this. Sorry for THREAD HIJACK.

 

Updating this thread, I know its been a while. Anyway I sent my injectors into FIC to have them tested. I really didnt think they were faulty but I wanted to be safe. Well sure enough the injectors were in great shape and matched almost perfectly 1004cc, 1004cc, 1004cc, 1008cc. With that being said I am now confident that I too am a victim of the infamous p0300 misfire code. Oh well, Im glad nothing was actually broken. I just wanted to give this update in case anyone was sitting on the edge of their seats awaiting a resolution.

Also, I wanna say thanks to everyone on here that has helped me. I also want to say thank you to FIC. I've dealt with a ton of companies and now dealt with FIC on multiple occasions and every single time I have spoken with them they were professional friendly and just downright helpful.