[Buffalo]

I am using a Perkin Elmer combustion analyser to measure CHNS of solids.  My signal timing often shows a sharp peak before the Carbon plateau and the data are grossly inaccurate.  Fill times are always perfect and the instrument gives no error notices.  The peak appears and disappears from sample to sample with no warning and or reason.  Has anyone seen this before?  What causes it and what can be done to remove it?  I sometimes have luck running a short He purge before analyzing a sample but that doesn't always work.