Oxygen Sensor starting to go?

Dec 31, 2006 4 Replies

Dear Lexus Experts - Have just started having some intermittent problems with my 2000 ES300 (58,000 miles, Northeast USA) turning over OK on turning the key, but not "catching". The car immediately stalls out, and it sometimes takes a number of tries and depressing the gas pedal until it idles on its own. As usual, once it's running, it's smooth, quiet, and performs as I would expect. Any ideas on what might be failing?



Thanx, Pete


Several things can cause the symptoms you are describing. Check the air filter to make sure it is not clogged and the passage out of the air filter does not have any debris accumulated in it.

The cold start enrichment system may not be working. Check to make sure the coolant temperature sensors are hooked up. If you have a volt meter, check for increasing voltage out of the sensors as the coolant warms up.

Check the MAF sensor to make sure there is no gunk accumulated on the wire inside the tube that sticks out into the air stream.

If all that stuff checks out, have the fuel pressure checked to make sure fuel pressure is not dropping while the vehicle is parked. If it is, check the fuel pressure regulator.

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