drift slut_fd

i got a 93 fd II......1st problem when the car is in gear with the clutch in just idleing...the rpms jump up and down within like 400rpm....but if the car is in neutral it idles fine....fuel problem?????....2nd problem...when i go through the gears and rev it past 5500 i only get half boost on the next gears but if i keep it under about 4500-5000 i get full boost (8.8psi)...checked for boost leaks and dont have a clue other than possible fuel problems...any suggestions would help alot thanks