Hey guys, cheers from Calgary, Canada! its my first post on this site so go easy on me I have a 92 gtst with the standard rb20det. to keep the long story short it misses in high rpms ONLY under boost.
I have pretty much tried everything, taken it to many places yet no solution. When i first got the car 2 years ago the throttle was very jumpy and overly sensitive. So that turned out to be my tps being set at 0.11 and Cas was turned completely CWW. And that time it was running fine but felt like there was no top end power after 5k. After the tps adjustment and CAS being set at 15. Car feels like it has more power up until u hit 4k it just sputters and bogs.
However if u just tap the gas and wait for the rpms to climb slowly it does it with no hesitation.
Here is the list of things I have done so far:
-changed the plugs to ngks irridiums last september gapped at 0.8mm (re chaecked them and they are still ok)
-Changed fuel filter and fuel pump with walbro 255
-cleaned maf with sensor clean (helped with response but problem still there)
-Octane booster, seafoam
-set tps at 0.46v ( made the the car idle at 1200 rpm.....)
-checked coil packs, visually they seem to be fine
Any suggestions??????
Thanks