Random Idle Issue

[remmargorp]

I finally got around to replacing my heater core. I was following the manual, first step was to disconnect the battery, next was to remove the instrument panel. I disconnected the battery (hot and ground), then something came up so I let it sit (perfect weather out, by the way), came back a few hours later, had to leave in it so I connected the battery back and started it up, the idle instantly dropped to 500 and stayed there, vibrating the car sounding like it was going to stall. When shifting, it would drop down to 500, lights would brown out and then idle at like 650. Normal idle has been 800-850 for the car (2 months of driving it). Disconnected the battery, waited about 15 minutes, reconnected it, same issue, drop down to 500 rpms... then maybe after a minute it would raise to 600-650, driving it, the rpm's would drop to 500 browning the lights out and going to 600. This morning I went out, started her up, idled perfectly, has ever since.

Anyone know what would cause the initial idling issue, the only thing I did was disconnected the battery, no hose's or other electrical connections were changed/bump/pushed/disconnected.

 

[steve]

Disconnecting the battery reset all the ECU long term variables, so it had to relearn them.

Steve

 

[scaryc]

mine does the same thing whenever i mess with the battery, except mine stalls out a few times instead of just idling low, after a while of driving it runs normal