More Engine Problems...
Reply #5 –
A few things that can cause a continued high idle...stuck IAC motor, faulty TPS, ECT, or even ACT in some cases. Rap on the IAC with the handle of a screwdriver while it's idling...see if there is a perceivable idle change. I highly doubt you have a drain on the battery...if you let a car sit for months at a time, the battery is going to die...the ECU requires a minimal amount of voltage for it's memory...if it's going to sit for months at a time, disconnect the ground cable fromt he battery.
Good luck,
Don
P.S.- I would lean more towards the IAC motor, if it's not that, then I would look to the TPS...probably the two most likely of your problem.