Changed timing belt and now the Z pulls hard from 3000-5500rpms but from 5500-7000rpms it feels like its running out of breath, is this normal on stock turbos? JWT chip running 14PSI. 615cc injectors. Single POP. Plugs @ 35. Reason i could not tell before is because the timing was messed up so it did not have a lot of power at all. Most noticeable in 3rd gear.