Stuttering 1990 300zx TT after 5000 RPM

The car takes off fine up to 5000 RPM, then starts to stutter through the redline, then continues to accelerate after the shift with awesome power, but then stutters after 5000 RPM's again. I've been told I may not be getting enough fuel past 5000 RPM's. Readings don't indicate that. I've also been told a plug or 2 may be bad. I'm running Denso Iridium Power Spark Plugs, (colder IK24) 5311 (part number). The Turbos spool up at am getting max boost without any leaks and no signs of detonation. What's up? Help?!?

Originally posted by FlexinTwinZ
The car takes off fine up to 5000 RPM, then starts to stutter through the redline . . .

It sounds like the turbocharger wastgate is seizing, or not opening freely. Have you checked the wastegate valve and actuator operation?

There could be a number of possible problems, including lack of oil supply to turbocharger; damaged turbocharger bearings; dirt/oil deposits caked on compressor wheel and/or diffuser vanes; fuel system defective or not properly adjusted; dirty air filter; and restricted exhaust or block cat.

Have you scanned the ECU? If so, what was the readout?

I found out the next day it was the large "s" hose that connects to the back of the balance Tube. It was crimped when I put the plugs in. Thanks though!