2002 Lexus RX 300 • 6 cylinder AWD Automatic • 210,000 miles

I have an 2002 RX300. Recently the engine light came on and gave 2 codes: P0136 bank 1 sensor 2, and P0171 systen too lean. So I ave an O2 sensor to replace. Then this morning the battery was almost dead because a relay in the engine compartment was clicking all night and the fog light was flashing as well. When I got in the car, the security light was also flashing sparatically. I removed the "short" jumper in the fuse box in the engine compartment where the clicking relay was, and the sound stopped. Of course some other things got disconnected as well, like the console screen, but after the car was boosted, it ran fine. Later in the day I plugged the "short" jumper back in, but the relay didn't start clicking again. So I'm confused. I don't want to end up getting stranded with a dead battery! I did a little internet research, which suggested some corralation to aftermarket autostart installations. But I couldn't find a fix. Any suggestions? Is this a common problem? Thanks
May 8, 2011.

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