my car (2000) transam ls1 M6

MODS
ls6 intake
bbk 80mm tb
long tubes no cats
slp lid
slp maf
dyno tune
ls7 clutch
ebay short throw

ran perfect all summer no issues it has been sitting since october and taken out and drove or atleast started every 2 weeks. well last week i went to go run it and the battery was completely dead so no big deal hooked the charger up to it. it finally started taking a charge after about 15 min of messing with it so i let it charge for like 3 hours came back and started it but it didnt go into high idle like it should. it started but wanted to try and idle at like 200-300 rpm and kept climbing VERRY slowly probibly took 30 seconds before it got to 800 rpm (never actually went into high idle) well i went to go drive it and see if i could bring it out of it every time i push the clutch in and let it idle down say at like a stop sighn it would go and idle slow then pick itself back up again and it kind of makes it a pain to drive because it tries to drop a lot of rpm between shifts.

any body got any idea what this could be what could cause this out of no where.?

 

since the battery was completely dead the ecu is just relearning. it will get better the more you drive it.