Hi Steve! I sure hope you wanted to say 700 - 1000 RPM ;). I don't think this engine is even capable of reaching 10000. You said that the car sat for 5 months. Did you drive it yet? Or was it just idling? If you didn't drive it then go outside, get into your D and drive it! It's FUN ;). Drive it for some 20 - 30 minutes - highway preferred. It is possible that your O2 sensor might start working again. Of course if the sensor has more than 30,000 miles on it it's time to replace it. Hope this helps Tom Niemczewski VIN 6298 (FOR SALE) tomciodmc@xxxx ----- Original Message ----- <SNIP> I started it up for the first time in 5 months and it started with no problem at all. as the engine sat idling for a few minutes until it reached > operating temperature it ran like a champ. As soon as it gets to > normal operating temperature the idle starts to fluctuate between > 7000 and 10000 RPMS.