Hello All, I am in need of some good advise on a problem I'm having with my '99 RX300, 93,000 miles. A while back my RX was running like crap and I was getting a flashing check engine light. The codes I was getting were bank 1 random misfire and bank 1 running lean. After about a month of troubleshooting, I finally figured out that it was the Bank 1, O2 Sensor #1 (air/fuel sensor). The sensor was bad and it was giving a false lean reading to the engine, causing the injectors to shoot too much fuel into the cylinders and thus causing misfires. I replaced the sensor and since then the car has been running great.
After replacing the Bank 1, O2 Sensor #1, I started to get another check engine light reading P0136 (Bank 1, O2 Sensor #2), although the car is still running good. My question is in regards to what could be causing this as I've heard that this sensor should last for 200,000+ miles. Could my catalytic converter have been damaged when I was getting random misfires and the false lean reading by shooting hot fuel into the cat? Or could the sensor be legitimatly bad? I bought a new sensor but the old nuts are so rusted on that I can't get them off. If I cut the bolts I won't be able to get the new senor on. Any advise is greatly appreciated! Ryan
PS - I'm in the Army and leaving for Iraq in two weeks and want this fixed for my wife before I leave.
