what, no start?

Walked out of restaurant last night and the XJ ('90 140K miles all stock) cranked but wouldn't start. Battery near death within 2 mins.
The IAC has been in need of a cleaning based on recent high idle. (I pulled the connector and did the usual on-the-spot wire twist but no good.) Been running fine up til last night-- thanks for any help.

no drop in rpms at any time? Soem things to check:
CPS, TPS, ICM (thats what went out on me) coil. Check for spark.....