cad1292

My 2004 4 cylinder (automatic) Camry now revs to about 2000 RPM when started with engine cold before dropping to around 1200 after a minute or so. RPM on warm start is around 1450 RPM for a few seconds before dropping. After warm-up the idle is normal (around 800 RPM) and the engine runs smooth. I cleaned the throttle body but that did not help. Has anyone had this problem?

I have a P2238 code on my 2004 Camry with 50K miles. Most of the listing on the internet point to replacing the air/fuel ratio sensor and reflashing the ECM to solve the problem. The Toyota shop manual shows that the A/F Ratio sensor should have a resistance of 1.8 to 3.4 ohms between terminals 1&2. My sensor reads 2.6 ohms which implies its good. No continuity between terminals 1&4 which agrees with shop manual. Should I have the ECM reflashed by the dealer and not change the A/F sensor or should I buy a new sensor? Other comments relative to this P2238 code would be appreciated. Thanks.