  We present analysis of RXTE--PCA observations of GX 1+4 between March 3, 2001
and January 31, 2003 together with the CGRO--BATSE X-ray flux and frequency
derivative time series between 1991 and 1999. From the timing analysis of
RXTE-PCA observations, we are able to phase connect pulse arrival times of the
source within two different time intervals and obtain corresponding timing
solutions. Using these pulse arrival times, we contribute to long term pulse
frequency history of the source. We look for episodic correlations and
anti-correlations between torque and X-ray luminosity using CGRO--BATSE X-ray
flux and frequency derivative time series and find that correlation state of GX
1+4 seems to change on $\sim$ 100-200 days long intervals. We estimate torque
noise of the source and observe flickering noise ($f^{-1}$). We achieve to
measure the longest observed timescale for a noise process among accretion
powered X-ray pulsars by extending the noise estimate for a time scale ranging
from 31 days to 44 years. Spectral analysis of individual RXTE-PCA observations
indicates a significant correlation between iron line flux and unabsorbed X-ray
flux. Pulse phase resolved spectra of the source indicate a broadening of iron
line complex at the bin corresponding to the pulse minimum.
