Occasional timeouts on TRUNCATE and simple INSERTs

Hello,

I am seeing some strange performance on a new pg9.1 instance.  We are seeing occasional statement timeouts on some
TRUNCATEsand INSERTs.  In both cases, the statements are quite simple: 
   - TRUNCATE schema.table;
  -  INSERT  INTO schema.table VALUES  ($1,2,$2,'');

Sometimes these will succeed.  Occasionally I see timeouts.  The statement_timeout is set to 60 seconds.  These tables
arenot particularly large; in the case of the insert, the table only has three rows.   

Our previous Postgresql 8.2 instance did not have this problem.  Any ideas about how to track down the issue?

Thanks,

--Jeff O