Bob,

I think you're ruuning into parameter sniffing problem
http://pratchev.blogspot.com/2007/08/parameter-sniffing.html

>All,
>
>What is a good way to create a maintenance plan in SQL Server 2005? Basically, I want to recompile all my stored procedures on a nightly basis so that data statistics, etc. are updated so that stored procedures run with the latest information on the data.
>
>I have experienced situations where stored procedures timeout (based on 30 second timeout parameter), but when I recompile the procedure manually, the procedure then runs very fast (2 seconds).
>
>I remember years ago creating a data maintenance plan in SQL Server Enterprise Manager (SQL 2000?) that did something like this, but this is no longer available in SQL 2005.
>
>TIA
>
>Bob