fflapjjack

Driver side headlight went out a few days ago and I finally got around to replacing it. Upon doing so I had to take out the battery. When I went to put the battery back in the car I connected the right (facing the car) contact first. When I went to connect the left contact it began to spark. Once fully connecting the left contact the sparking stopped. When inserting the key into the car all of the interior and exterior lights came on as I expected (including newly replaced headlight). When starting the engine the car turns over but does not start. If I push on the gas when starting I can get it to run but as soon as I let go of the gas (rpm meter drops) the engine turns off or the whole car starts to rumble and hovers at a really low rpm. I am not very car savvy and am pretty sure I did something to the car when removing the battery. Any help would be great!

tomf

Based on your description, I'd say you have an idle air control valve (IACV) problem. Probably just needs cleaned. https://www.clublexus.com/forums/rx-...-write-up.html I don't think the battery has anything to do with it. I could be wrong though.

FYI for the future, always remove the negative cable first and install the negative cable last on the battery.

Oro

I think Tom is on the right track, but I think more likely what happened is you disconnected one of the many air hoses in close proximity to the battery tray. Check those out thoroughly.

speedkar9

2003 doesn't have idle air control. Throttle is drive by wire.

Its likely you have a vacuum leak caused by a disconnected or broken hose. That causes the engine to run too lean and the ECU can't compensate because the leaked air isn't picked up by the MAF.

You could also allow the engine to warm up until it reaches operating temp and see if it will keep idling. When the battery is disconnected, the ECU needs to relearn the idle procedure.

LeX2K

Could be a vacuum leak but sounds more like a MAP/MAF sensor problem. Maybe a connector was bumped or damaged.