Well i have replaced o2 sensor, Coil Pack, Plug Wires, Spark Plugs (gapped to .30 NGK BRP7ES). I have no idea what else to check. I looked at my came gears and they are lined up. It started throwing this code after I did my act 2600 install but i rechecked everything i touched during the install. I do not have a 6 bolt so that isn't the question so now i am just looking for suggestions on things i may have over looked.

Try getting stock BPR6ES plugs gapped to .29. You don't need 7s until you are running 20+psi on a 20G or larger.

I don't recall what turbo you do have, so if you have something that size, ignore my comment.

What type of misfire? Is it just a CEL or an actual physical misfire? What RPM? Does it happen at the same RPM all the time, or more random?

I am getting a code P0300. It only happens on the highway in 4th and fifth gear. If i let off the gas and take it out of gear for a second it usually goes away. I just heard from two people that my Fidanza Flywheel is causing this issue as it has happened before. Appearantly the Flywheel is too light. I am going to do some research to see what i can find related to this. I am running the Big 16g @18psi so i will try the other plugs. I really don't believe it is plug related since it is not happening in the same cylinder all the time. Id on't know tho....like i said, I am fresh out of ideas.

This was just explained to me Jeff...what do you think?

"The way the car checks for random misfire: it checks the crank speed. If the crank slows down under a certain power stroke, it assumes that piston is misfiring. The formula used for this is based on a heavy crank/flywheel that will spin at a certain rotational force. Put in a very light flywheel like a Fidanza and the crank can slow down and speed up so quickly that it fools the computer into thinking there is RM. It happens on some cars often, hardly ever on others, and some almost never get a RM code with a Fidanza.

It happened to me when I had my Fidanza put in, luckily I already had DSMlink and could turn off the random misfire check. Without DSMlink, I dont think theres any way around it."


From now on i will research EVERY SINGLE PART the goes on my car.

Do you actually feel the misfire, or is it just a code?

That explanation is correct, but does not always relate to lighter flywheels. My old roommate's 97 TSi AWD was automatic with the stock flex plate and torque converter and pulled a misfire code all the time. It was never actually misfiring, it just threw the code. If you do not feel the misfire, you don't need to worry about it. His car ran 11s with the misfire code, so you should be okay :)

Tons of DSMs use the Fidanza flywheel with no problems, so I wouldn't rush into changing that any time soon.

nah....I am not going to change it out. I am eventually going to get DSMLink to fix my issues. Yes i feel it misfiring from time to time on the highway only. When daily driving, it isn't an issue. I am just glad i found out what it was, and that i was not hallucinating.

my car did the same thing, i let it sit all winter and it went away.
my battery was dead when I went to start it up. So unhook your battery for 30 min to an hour and then see what happens. I think mine was caused by me setting the boost too high and hitting fuel cut, I assume it stopped cutting after I set the boost to normal and resetting the ecu (unhooking the batt.)

Originally posted by theallpowerfulme
my car did the same thing, i let it sit all winter and it went away. my battery was dead when I went to start it up. So unhook your battery for 30 min to an hour and then see what happens. I think mine was caused by me setting the boost too high and hitting fuel cut, I assume it stopped cutting after I set the boost to normal and resetting the ecu (unhooking the batt.)

I have no idea what you are talking about. Mine was caused by my lightened flywheel. IT was physically misfiring while cruising on the highway from time to time. Clearing the code and ECU did not stop it. I fixed it with DSMLink. Car now runs fine.