bought my Evo 8 about a month ago now. it has an MBC, intake, hard pipes, and cat-back.

in any gear, from 4900+ rpm it is hitting a hard fuel cut and stuttering all the way up the RPM range. ONLY at WOT, i can be at 17-18psi and it is smooth as butter, but as soon as it goes WOT it stutters.

Could this be from the previous owner messing with the MBC and therefore the boost tables? I have checked all the clamps and hoses over once, but just the fact that i bought it from a young person who told me "you can just twist this knob and bam, you get more power", makes me think he went wild turning the knob like a strippers tassles.

I emailed the company that installed the MBC and tuned (Touge Factory) to see if they keep a log of work and what the car was tuned for.

for the time being, would it be best to just adjust the MBC down to decrease boost?

thanks!

 

also check your spark plugs... i had a similar incident where i had crazy backfires and fuel cut only at wot and finding out my plugs were bad

 

if my plugs were bad, wouldnt at least one of the dozen stutters trigger a misfire code?

 

Check plugs first for proper gap. Too much gap you can get spark blow out.

 

Your not hitting fuel cut, if you did, you would know immediately. As others have said check your plugs, but also check the hose to your wastegate.

 

Im having the same issue but as soon as i hit full boost/load. Violent shaking front the front. Like Im hitting a wall.

Part throttle pulls cleab to redline. I think its in the tune.. needs to be adjusted. I have a mew one Im going to put in tonight.

Going to swap plugs, boost leak test, and look into the front o2 sensor. Keep me updated on your car amd i will do as well.

 

mine didnt throw any codes for misfire good luck

 

I had the same type of issue, changed plugs and wires to the magnecor's from MAP, no more issues.

 

unfortunately i received an email back from Touge factory this morning. they did install an MBC and coils, but never did a tune. so as far as i know, there is currently not a tune on it, which is quite aggravating. Luckily i ordered my tantrix cable already. I will be getting new plugs this weekend as well.

is there a reason it doesnt have a code for misfires triple L?

 

very good question... this idk i did a bit research and these engines recommends ngk spark plugs gap at .20-.25 and at the time i had new champion iridium plugs gapped at .27 and started backfiring like crazy...my tuner told me to go back to stock plugs.... forgot the part number but they are ngk iridium and everything went back to normal