KO4 Not making full power. mystery issue please help. logs included.


New member
I have been chasing this issue for months now but still between me and my tuner it still hasn't been fixed.

The car will pull ok but its defiantly not at full power. Most pulls i do i don't see a maf g/s reading that's higher then 240g/s which is defiantly a bit low. But I can confirm this is a real issue and not just me being dumb in the head. In the data zap graph. you can see my maf g/s go up to around 260 and my load meets requested before they both drop back down. I will also make sure to note that my stft dip down to around .89 when this happened and it has happened at different points on multiple pulls in both 3rd and 4th gear.

This other picture is my throttle input. my foot is to the floor the entire time but it seems for most of the pull the car drops the throttle from .95

In trying to fix this issue i will list the things I've done. if i forget anything i will add it later.

Changed Map
Changed Maf
Boost leak tested 4 times.
Changed plugs
Changed coils
Changed n75
Changed Diverter valve
Changed pcv (only boost leak i can still find is a very small leak from the hose between the pcv plate and intake manifold. it leaks from the connection but i have to wiggle it for it to leak.)

Car parts list.
CTS intake stock maf housing
CtS ko4
Ebay catless downpipe
r8 coils
ngk something something 8 series iridium plugs gapped to .0022
that's every relevant engine related mod.

Datazap links.


Autocross Champion
What tune (company)?

I gap my plugs to .028


Ready to race!
Like others have asked, curious what tuner you're dealing with.

.022 is a little tight on plug gap, I would go .026-.028

Have you done a compression test?
Is the engine in time?

Your MAF readings are kind of bizarre given the boost levels you're at. Also curious why you only have knock retard cyl 3 logged and not the other 3 cylinders?


New member
.022 is what the tuner recommended but ill bump it to .026. sorry I kind of left the thread dead. i had notification off and didn't even realize people responded.