So just randomly a few weeks ago i started having issues with the higher rpm range. Car runs normal and strong, and pulls hard up top but it seems like its mis-firing or falling on its face around 8k rpms. My redline is at 8900 rpms and my shift light is set for 8300 rpms, at around 7800 rpms it kind of "pops" almost like im hitting a rev limiter, and i did an s2k cluster conversion and when i stare at the rpms and there climbing at around 7800 rpms they dont climb steadily anymore, actually the pegs/rpm indicator goes up and back as it climb's

it was tuned great a few months ago

set-up'

00 jdm itr swap
i/h/e
s2s1 cam shafts w/skunk 2 cam gears
msd ignition, msd external coil, msd cap, msd rotor
hondata s200 w/p28 ecu
aem fpr

Now i just changed my plugs this mourning to RM plugs and gapped them at 40, i also changed fuel filters and gave it some fresh oil. Problem dosnt seem to be as bad, during a drive today the rpms still kinda seemed "odd" around 7.8k+ but it wasnt making the popping noises how-ever if watching the rpm bars it was going up/down as it was primarily going up once above the 7.8k range'....Not throwing any codes

all ignition components are only 4-5 months old and my car is only driven a few times a week'

I may try to get an hour of dyno time and see if the problem shows up on paper or if im just being paranoid but it seems like an issue to me'

 

I'm having a similar problem. Does the coolant in your reservoir and radiator have any brown sludge in them?

 

yeah, check that out!

 

nope, my coolant is clean

and what would that have to do with mis-firing? mis-firing is typically an issue with fuel or spark/ignitition