Well everyone I just about had it and I need some advice on this car. I have an evo 9 with gsc stage 2 cams. I recently got the car tuned not sure if it was handled properly. Now heres the situation I have a code that just wont go away no matter what.

I know the p0300 has a misfiring code but its not tellin gme anything becuase it can be any of the cylinders. Whats the best thing to do from here let alone which are the best sparkplugs to use for it since now that its tuned how much do they cost and where is the best place to get them from. I need sparkplugs sparkplug wires and ignition coils.

 

First things first.

1. Before you do any of that. Contact your tuner and get their advice. If the code was brought on by the tune, then they should be able to look at it, and help you get it sorted.

2. P0300 is sort of a unicorn code for Evos. Mitsubishi has issued a number of reflashes to attempt to quell it, to seemingly no avail. There's good info floating around if you search google.

3. Is the car ACTUALLY misfiring, or just throwing this code?

 

Sorry I must've hit post...

4. It's most likely not happening in any particular cylinder. And it's probably more related to spark blowout than anything else. What boost level are you tuned for, and what are you running?

 

Does the code trigger on idle, cruise, WOT?????

 

It pops up after cruising at higher speeds and sometimes it pops up after I hit wot and when I cruise after that then it pops up. Its really annoying though.

 

running on the stock ecu with speed density boostin 20 to 21 psi.

 

Well im not sure of the sparkplug gap on the car but I will check in with the results buy tommorrow. I looked at it on the forums for p0300 it has to be something simple after I had it tuned.

It feels like it cuts out when im holding boost but im not flooring it when I have my foot down about halfway. So how should I check the plugs where should my gap be at as far as the tune and what sparklplugs should I get.

 

I have the same problem it pops out when ever it wants to but dont have an actual misfire and then just goes away, it started after my tune but have not gotten around to find a tuner to fix it.

 

Take a look in this thread...

http://evoatlanta.com/forums/showthread.php?t=84

 

Take a look at your timing and fuel maps. Seen large jumps from cell to cell in the mapping trigger P0300's

Also have heard of improper MIVEC mapping causing P0300s as well.

 

I disabled my p0300 code in my tune. No issues doing that here.

 

Def the route for the problematic cars. Mostly 03-04s that were plagued by them. Mitsu answer drivetrain harmonics causing the issue and their "fix", a couple ROM updates. Worked for some not for others.

With this scenario owner would say during highway cruise CEL will pop on car stumbles/shudders. Let foot of gas and back on and the car runs fine. Don't think I've seen a report of this scenario in a IX.

 

Ok im goin to start from the lowest point what its the part number for the step colder sparkplugs for ngk for the evo 9's and where should my plug gap be at?

 

I had this code yesterday, forgot to update my flash for my New Omni Map sensor. I have a new clutch so I have not done any WOT so it trigger's @ idle/cruising for sure

 

Okay giving an update my evo 9 was running 1LFR7H plugs. After pulling each plug I found out that cylinder 1 had a gap of 0.23, cylinder 2@ 0.24,cylinder 3 @ 0.23, cylinder 4 0.27 ouch wtf was the last owner thinking. Even with the car tuned I think that was the reason why it got sparkplug blow out at mid-range boost.