hi i have an 03 evo and still getting the o0300 code. my local deal wont flash my computer for the new 0015 rom since my car is modified and they state my car is misfiring at idle at 1000 rpms but when im in high gears and around 4k my check engine light comes o n. im running br7es for plugs gapped at .26

 

do you have a tactrix cable or know someone who does?

 

pmed

 

its weird cause im getting a random misfire. hope fully after the 015 fix ill be all set

 

I just had this problem the other day. On the highway my car stuttered and the CEL came on. I pulled the code with a reader and it came up as a p300 random/mulitiple misfire. I just replaced my plugs (gapped at .24) and have not had a problem since. You might try that. If that doesn't work, I would say its a coil.

 

I talked to my dealer about this and they said they can do a reflash that will cost me about $115. However, one of these days I wanna get my computer reflashed by dynoflash or something. If I go get this done at the dealer, and then send my ECU to get flashed for performance, is it going to undo what the dealer did? Or do I need to get this reflash from the dealer in order to get better results from a tune?

 

You could buy a cable and evoscan/ecuflash for the same price the dealer wants to charge you.

With those tools you can do all your own maps for free of charge after the initial purchase.

 

Does the fact that I know absolutely nothing about tuning a car matter?

 

ok this is what happening im driving hard then about 4k my car starts to sputter and my check engine light comes on. if i clear the code then punch it again the car is fine. so this misfire is randon and i beleave its bad coils or plugs well find out tomm

 

It is probably not bad coils or plugs. This is a common problem on 03 and 04 evos. All you need is a Tactrix cable and a laptop and you can put the updated flash on your car. Do not pay the dealer $115 for the reflash.

-Paul

 

here is the one of the best way that you'll not rip off by the dealer. Buy the tactrix cable, install EcuFlash, pull the map from your car, send it to one of many "nice" persons frequently participating in the EcuFlash forum. Your map will be "converted" to 0015 map and you can flash it back to the car. Converted here mean that an 0015 map with the air/fuel and timing maps copied from your old map, maybe 2-bye load added. This way, there'll be minimal risk of your fuel and timing maps running into issue. Good luck.

 

honestly i really think my car is missfiring cause thats what it feels like

 

A P0300 is a misfire the way it happens, but it does not mean it is an actual misfire.

Whatever the problem bug is in the code for misfire detection, makes the car act a little weird and misfires the car on purpose.

 

I would check the following in order and after each see if the problem goes away:
1. Check and make sure all your spark plugs are tight
2. Try a set of BR8EG's (these are "race" plugs but they work real well esp with meth)
3. Replace wires and boots (boots are on the bottom of the coil packs) with new OEM, DO NOT use magnacore wires
4. See if you can borrow a set of coils from a buddy


If the miss is happening as you roll into the throttle from light load, I would suspect the fuel trims to be a large part of the problem. Pull the negative terminal off the battery, let the car sit for 10 minutes, pump the brake pedal a time or two then re connect the battery and try again.

If it's fuel trim related, clearing the ecu will make it go away for a little while until the trim build back up.

If it happens well after you go WOT it's something else.

Dealer reflash never did crap for my P0300's. BR8EG's did though.

What are your modifications in detail?

 

I can get that 0015 rom into your ECU if you want to take a ride to NJ PM me I'd be glad to help