odd problem...won't rev over 4000 rpm no engine codes
 

I have a 98 1.8t that was running ok then one day started missing at 4k rpm exactly I replaced spark plugs and do not beleive its the coil packs as it runs great to 4k then just seems like it hits a rev limiter....ocasionally it will go higher but still misses....will idle for hours with no hickups...stock tune and 5 psi on boost gauge...never really had a good top end but just assuming these cars are slow stock but wouldnt break up just seemed slow...I've only owned the car for 2 weeks....any help would be greatly appreciated...I checked the codes via a ebay vagcom cable but couldn't recalibrate the throttle body as I guess ebay cables are pirated copies