I have a check engine light on and cleared it out, but then it came back a few days later. I checked the plugs and they were normal. I also checked vacuum lines and didn't notice any that came off, I zip-tied them all on. Any ideas?

 

Did you recently install cams? You can shut the code off. Just have your tuner reflash it and shut off the misfire

 

try some fuel cleaner and you check for boost leaks right??

 

What plugs? What gap?

 

I got the same thing after cam install. How do you Shut off the misfire

 

You just disable that CEL in your ROM. that way it doesn't come back on.

 

Do you know where in ECUflash to disable it? My car randomly throws 0300 and cams/motor/or tune was never touched.

 

there have been countless threads on this. it's a known issue with all EVO's. another cause for it is the harmonics of the clutch setting off a trigger for the code. there's also a mod to fix it offered by AMS i believe?

 

It doesn't hurt anything, it's just annoying.

I'm a Google search MASTER, this was the first result, hence everyone saying S E A R C H - http://www.youtube.com/watch?v=O24x0yfKYZk

If you've never messed with any of the ECU Flash or are not comfortable with doing it get a tuner to do it for you

 

Driving my 8, I'd get to the panhandle of Nebraska, headed for Wyoming, and the P0300 code would start to hit. Every time it hit it felt like two cylinders had dropped out. Then, if I pumped the gas pedal it would go away only to come back a few seconds later. I'd be doing this for the next 200 miles. So, maybe that is not hurting anything but it sure took the fun out of driving. And, when this first starting happening, I didn't know what was going on. I expected to be stranded.

 

so when you say "shut it off" does that just mean when your car misfires it won't throw the code??

 

Yes, the car will no longer report misfires. If you have a misfire problem, sort it out before doing this. Do you have cams installed? Lightweight flywheel?

 

Well right now I know I have a boost leack, it's my intercooler, new one just ordered, but before the leak started I would get it once and a while. Yes I do have a lightweight flywheel but it would do it once and a while before I had it installed. Thank you for clearing that up though!! It confermed what I thought

 

I used to get PO300 all the time in my car. Exactly like you described, annoying to drive, constant hesitation, totally took the fun out of driving.

There is a TSB at the dealer. They can do a reflash and fix your problem. If you still have a warranty, they should do it free. If you dont, I think it costs around $100. At least thats what it was when I looked into it.

The better route, just get a custom tune, then you can get the fix for your code, plus enjoy the extra power. IMO this is totally the way to go. It may cost a lil more, but its so worth the money. Also, the way it was explained to me by the guy who tuned me... the reason the problem occurs is that the computer is searching for this problem in error and actually causes the problem. Once he told the computer to stop searching, it no longer occured. I really dont know, but my car runs awesome now. The guy who tuned me is a member on this board. His name on here is Touring Bubble, and he could probably give you some tips if you ask him.

 

P0300 was sticking me in my a$$ too. I had CBRD clear it out form the ECU. Mitsu can do it but if you have a tune its from what im told gonna irradicate the ecu back to stock.