SQL Server timeout mysteries. asp.net=bad, query analyzer=good

[Simon Devlin]

Ok, I realize that this is vague, but I'm stuck :-(

I've a particular query that when executed from within asp.net times out
(after 30 seconds) If I do it from within the SQL Query Analyzer on the
same machine, it works fine (and in general takes < 2 seconds)

It's possible that it's connection pool exhaustion - the message that comes
up is the usual "timeout. maybe connection could not be
allocated...blah...blah", but if I kill the aspnet_wp.exe, that drops the
number of active connections as reported in PerfMon .clr data right back
down to way under 100. The problem still occurs, and the perfmon counters
don't increase that much, so I don't think it's that (even if I immediately
jump straight to the page concerned bypassing all the other data-based
pages)

I'm not expecting a firm answer here, just a couple of pointers as to were
to look next as I'm really confused.

All pointers happily received

Thanks