well... im driving down the highway at about 75mph and my car randomly misfires. im in 9 inches hg when it happens every time. i have no idea what it is. i replaced the plugs and wires. cleaned the egr. the code i get is a p0300 (random misfire). i took it to the dealer and they cant get it to duplicate. so i was wondering if anyone has seen this problem or it happened to their car as well. thanks

 

This sounds like the infamous tranny harmonics issue. You have an 03 and I assume you've got a good amount of miles on it. Your 5th gear is probably worn and input shaft has developed play which assists in the knock sensor going off. You are not alone.

 

^ i was thinking the same. How many miles do you have on the car? stock tranny?

 

hell i get the p0300 and p0304 on my evo ix with 16k miles.

 

i got 97k on it. so what do i do to fix this problem?

 

Its sad when random people on an internet forum know more about a car than the dealership that sells them.

 

yes it is.....

 

With on 03 evo 8 I thought the dealership was reflashing for the p0300 codes... Any help with this anyone?

 

i have no idea. the dealer did tell me anything when i took it there. they just told me i have a random misfire

 

I got the same code for the last month since my rebuild...

I've cleared it before, and it happens couple days later while i'm idling, so it's obviously a false misfire, but I've done all this to try to fix it:
have changed the plugs
gapped them less to .024 instead of .028
5th gear is fine since it's a shep tranny and has less than 5k miles on it
vacuum/boost lines are all tight
tune is fine, not rich or lean, at 14.7ish at idle
...nothing worked lol

 

Yea i have it too, i think it is relative to having an ACT clutch and prolite flywheel... it never happened until i put that on, it is a little more audible then stock. Also yes the dealer is stupid, i was going to trade it in(decided not to) took it to them and i had just worked on it, and an intercooler hose blew off and they told me that my turbo was shot... i said oh really... open the hood look around for a bit.. and see the problem... and tell them thats why people think you guys are stupid... because you are and left.

 

I have an '03 evo also and it started to have the misfire problem shortly after I bought it. I went to the dealer told them the issue and the guy there said its something they cover under some sort of recall order and then they rebuilt my fifth gear and changed out all the syncros for my tranny. This was around 10k ago and now its having the same problem all over again

 

No F-ing way! I called Mitsu USA directly to see if there was a recall due to the 5th gear syncro/input shaft problem, and they told me the only recall on 03 evo's were for a certification tag. They totally denied me any resolution. Mind you this was Mitsu, NOT a stealership. WTF?! You need to tell me how you got this done, because everyone I have talked to says I am SOL.

 

yeah this guy at the dealership totally just set me up. He saw my issue and had all the work done. He was pretty cool.