After doing searches I can't find if anyone really solved this problem. I keep finding people theories but that's about it. Whenever I drive on the freeway holding aprox. 75-80mph i would start the get a random sputter and the car will lose power for a little bit but if I let off the gas and reengage then the power is back again which makes me believe that there really is a misfire. So I read that a colder plug will help, timing off, tranny vibrations, needing a reflash? If the timing were off I would assume the car would run terrible to begin with. Colder Plugs seems plausible. Tranny vibrations won't solve my loss of power. And reflash maybe but I have the Cobb acn stage 1. Any help would be appreciated!

 

What you feel is the ECU's response to the code being thrown. A limp mode if you will. Drivetrain harmonics are mitus ultimate answer to the issue and put out 2 rom updates to combat the issue.

Best bet for the really plagued cars is to just have someone disable the code routine in the ECU and the scenario you described will never happen again

 

random missfire, could be the spark plugs, the ignition coils, could even be one of the injectors, one of my injectors went bad so I was missfiring aswell, hilarious story, my car sounded like a subaru LOL

 

you have an '03 evo. There is a TSB out there that covers the drivetrain harmonics with the 5th gear assembly that can cause the Knock sensor to chuck a code.

Also, search in the ECUFlash forum, there are solutions out there that can help you tune out that problem, or you can do what I did and turn off that particular CEL...

 

The first time I got the code I figured it was the spark plug. The dealer put bpr7es in the car when I bought it. So I put some iridiums bpr7eix in it figuring it would help. Then I got the code again and then I took the iridiums out and it looked like they were running a little lean since there was some white buildup. So I put in new plugs again and it threw the code again. From what I read most of the time injector problems happen when the car is running rich. So another thing that can be a possibly be a problem which I thought nothing of it is that the spark plug wire separates from the boot but when I put it back together it seems like it's fully on there hence why I assume it's not a problem.

 

Chris and gsrboi already told you the issue. You're going to wind up chasing your tail to stop it. Have your tuner disable it.

 

You have an '03. Maybe there is an '03 out there that has never thrown a p0300 code but it would be a rare vehicle.

 

i have an 03 and had the same problem. code used to come on everyday! then i change to 1 step colder and it would come on ounce a month. i told my tuner about it, so he decided to change my rom to a 05 rom. no more po300 for me

 

Its true you really do have to get someone who knows what they are doing to fix the problem. I bought my 03 a year ago and the problem has progessively gotten worse to point where i cant even go full boost without the car going into limp mode, and thats in every gear.

Ive done a lot of research and here is the problem too the best of my knowledge. All of the input shafts in the transmissions for the 03 evos become very lose after 30k plus miles are put on the engine. The code doesnt pop up in just 5th gear, it happens more frequently in that gear because rpms are increasing at a slower rate. if you place it in 3rd gear and cruise up to 3k rpms for a little bit it will happen then too.

One thing that helps is to buy a code reader. Its pretty detailed but the bottom line is that it keeps the code from happening when you the reader plugged in at all times. That would be the cheapest method. It worked for me but i still cant go 100% throttle. The next thing you can do is what others have been saying and that is to get a tuner to fix the problem on your ecu. The best and safest thing to do is to replace either the draft shaft in the transmission or just buy a new tranny. While your at it just go ahead and buy a bilt shep tranny or buchwhacker.

 

ECU Periphery2 (FCA) Bits

P0300; set bit.4 and bit.5 to 0 to disable


do yourself a favor and upgrade to 94170015 v7.

 

How many miles do you have? I had this problem. I noticed a rhythmic droning that I could hear at high way speeds... this was triggering the po300. I got my tranny rebuilt at shep and the problem went away for good. the problem started at 70k, got my tranny rebuilt and to 150k miles had no po300.

 

For the first year I had my car, I would get the p0300 issue. After a year of the dealer promising me a reflash once it became available, they renigged on me even though they put the promise in writing.

So I ended up chasing down the issue myself and figured out mine was completely an electrical issue after a month of being experimental. Turns out it was my ignition causing mine, a combination of my greddy turbo timer and of faulty/ intermittently failing ignition coils, which intrigued me on account of it being a brand new car. I replaced both and I never had the issue since.

 

There is a thread in which one person said he was able to tune it out. I will look to see if I can find it again. I just disabled my years ago and still have no issues.

 

There is a thread called "spark plug recommendations..." post number 13 by Slo_crx talks about an alternate way. I have not tried it out though. I will post a link once I get back to a computer. I am using my phone and its being a pain.

 

yeah why tune it out when you can just turn it off?